-
Which tool should be used in Inkscape to create custom shapes by editing nodes and curves?
- a) Rectangle Tool
- b) Circle Tool
- c) Pencil Tool
- d) Bezier Tool
(The Bezier Curve tool is used for drawing lines and curved shapes, and the Edit path by nodes tool is used to curve or adjust lines....)
-
What happens when two shapes are combined and selected in Inkscape, and the 'Path → Difference' operation is applied?
- a) The two shapes combine to form one.
- b) The part where the two shapes join is removed from the figure below..
- c) Copies of both shapes are created.
- d) The two shapes are divided into two parts.
-
What happens if you set the Transparency of an object to 0% in Inkscape?
- a) The object becomes transparent and cannot be seen.
- b) The object turns white.
- c) The object turns black.
- d) The object is removed from the canvas.
(The Opacity adjustment is used to control the transparency of colours.)
-
What is Scribus mainly used for?
- a) Video editing
- b) Photo editing
- c) Desktop publishing
- d) 3D modelling
(Scribus is a popular open-source Desktop Publishing software used for designing magazines, books, and newspaper pages.)
-
What is the use of Text frames in Scribus?
- a) to draw shapes.
- b) to type sentences and format them.
- c) to include images.
- d) to colour the background.
(Text frames are required to include and format sentences in Scribus.)
-
a=100
a=a+25
print(a)
What will be the output of this program?- Answer: 125 (Calculation: 100 + 25 = 125)
-
Which is the python program to print even numbers from 20 to 40?
- a) for i in range(20,42,2): print(i)
- b) for i in range(20,2,42): print(i)
- c) for i in range(20,42): print(i)
- d) for i in range(1,2,20): print(i)
(The range statement systematically arranges numbers.range(start, end, step)is used, where the sequence increases by the step value.)
-
What is the name given to the information that is being produced in large quantities, rapidly and in different ways in cyberspace?
- a) Digital Footprint
- b) Bigdata
- c) Cyberdata
- d) Indirect information
(Big Data refers to very large and complex datasets generated rapidly in cyberspace that traditional data processing software cannot handle efficiently.)
-
Identify the odd one which do not include in Digital Assets.
- a) School Computer Lab
- b) Software
- c) Reward point from Bank
- d) Digital Image
(Digital assets are financial assets that exist only in digital form, such as digital currencies, software, and points from online shopping.)
-
Which style feature is used to bring the text in a webpage to the centre of the page?
- a) color: #a569bd;
- b) font-family: Gentium Basic;
- c) text-align: center;
- d) font-weight: bold;
(The instructiontext-align: center;is used to align text to the centre.)
-
<h3 style="text-align:center;color:#a569bd;">Hand-made Notebooks</h3>
Which cascading style is used in this line?- a) Inline
- b) Internal
- c) External
- d) Outline
(Inline cascading styles involve adding styles directly using the style attribute within the opening tag of an HTML element.)
-
While using external cascading style sheet, which tag can be used to include the stylesheet in an HTML page ?
- a) rel
- b) type
- c) css
- d) link
(The external CSS file is linked using the<link rel="stylesheet" type="text/css" href="filename.css">code in the<head>section.)
-
Which of the following can be used as an actuator in a robot?
- a) IR sensor
- b) Servo motor
- c) LED
- d) Arduino
(Actuators are components enabling automatic movement, and servo motors are an example of actuators.)
-
Analyze the code given in the figure and find the correct statements given below.
- a) An output device is connected to Digital PIN 4.
- b) An output device is connected to Digital PIN 10.
- c) An input device is connected to Digital PIN 4.
- d) An input device is connected to Digital PIN 10.
(Note: The figure/code necessary to analyze the correct statement regarding pins 4 and 10 is not provided in the source material.)
-
Which of the following planets makes it impossible to observe celestial bodies in the Stellarium software?
- a) Mercury
- b) Venus
- c) Uranus
- d) Neptune
(Note: The source materials do not contain information specifying which of these planets cannot be observed in Stellarium.)
-
Which of the following locations in the Stellarium software can be used as an observation point to view the midnight sun?
- a) Alice Springs
- b) Kuala Lumpur
- c) Sydney
- d) Talnakh
(The midnight sun is seen in areas beyond the Arctic and Antarctic circles. Talnakh, Russian Federation, is located at a high latitude (69° 29’ 11.41” N).)
-
Which of the following is an online geographic information system portal?
- a) Quantum GIS.
- b) Grass GIS
- c) School GIS
- d) Map Info Pro
(School GIS (https://schoolgis.nic.in/) is an online geographic information system portal.)
-
Which of the following is not an open source geographic information system software?
- a) Quantum GIS.
- b) Grass GIS
- c) Arc GIS
- d) Map Info Pro
(Quantum GIS and GRASS are noted as free GIS software.)
-
Which of the following would be an equation for drawing a line parallel to the Y axis using the input tool in GeoGebra?
- a) x = 2
- b) y = 2
- c) x=2y
- d) y=2x
(Typingx=1creates a line parallel to the Y-axis.)
-
Which of the following constructions will be obtained if you type A(1,5) in the Input bar of GeoGebra software?
- a) Pint (Implied: Point)
- b) Line
- c) Circle
- d) Short line
(Typing coordinates likeA(1,2)in the Input Bar creates a point A on the screen.)
- The names of some rooms (workspaces) in OpenToonz software are given. Note down their uses.
- Given below are the icons of some important tools in OpenToonz. Complete the table with their uses.
-
Which one is used to distinguish the records of a table from the others?
- a) primary key
- b) foreign key
- c) fields
- d) private key
(The Primary Key is the field added to uniquely identify each record in a table from others.)
-
SQL means ................?
- a) Systematic Query Language
- b) Structured Query Language
- c) Structured Questions Language
- d) Sequenced Query Language
(SQL is the specialized computer language used by DBMSs, standing for Structured Query Language.)
-
Which of the following is not an open source software license?
- a) Apache Software License
- b) End User License Agreement
- c) GNU General Public License
(The End-User Licence Agreement (EULA) is associated with software that provides only object code and usage restrictions, such as Microsoft Windows and Apple iOS.)
-
Which of the following is free hardware?
- a) Apple mobile phones
- b) Arduino similar chipset
- c) Mobile phones with Android installed
(Arduino microcontrollers are an example of hardware released under open-hardware principles.)
-
What is the name given to free software?
- a) Free software
- b) Open software
- c) Freeware
(Free software prioritizes user freedom and knowledge dissemination.)
-
What is the shell in the GNU/Linux operating system known as?
- a) Open Shell
- b) Linux Shell
- c) Bash
(The shell component of the GNU/Linux operating system is called GNU Bash (GNU Bourne Again Shell).)
-
Which of the following is not an operating system?
- a) Android
- b) Linux
- c) Unix
(Note: All three options—Android, Linux, and Unix—are discussed in the source as operating systems or based programs for operating systems.)
- Which tool should be used in Inkscape to create custom shapes by editing nodes and curves?1
• a) Rectangle Tool
• b) Circle Tool
• c) Pencil Tool
• d) Bezier Tool2
(The Bezier Curve tool is used for drawing lines and curved shapes, and the Edit path by nodes tool is used to curve or adjust lines3....) - What happens when two shapes are combined and selected in Inkscape, and the 'Path → Difference' operation is applied?2
• a) The two shapes combine to form one.
• b) The part where the two shapes join is removed from the figure below..2
• c) Copies of both shapes are created.
• d) The two shapes are divided into two parts. - What happens if you set the Transparency of an object to 0% in Inkscape?2
• a) The object becomes transparent and cannot be seen.6
• b) The object turns white.
• c) The object turns black.
• d) The object is removed from the canvas.
(The Opacity adjustment is used to control the transparency of colours7.) - What is Scribus mainly used for?8
• a) Video editing
• b) Photo editing
• c) Desktop publishing8
• d) 3D modelling
(Scribus is a popular open-source Desktop Publishing software used for designing magazines, books, and newspaper pages9.) - What is the use of Text frames in Scribus?8
• a) to draw shapes.
• b) to type sentences and format them.8
• c) to include images.
• d) to colour the background.
(Text frames are required to include and format sentences in Scribus10.) - a=100 a=a+25 print(a) What will be the output of this program?11
• Answer: 125 (Calculation: 100 + 25 = 1251112) - Which is the python program to print even numbers from 20 to 40?11
• a) for i in range(20,42,2): print(i)11
• b) for i in range(20,2,42): print(i)
• c) for i in range(20,42): print(i)
• d) for i in range(1,2,20): print(i)
(The range statement systematically arranges numbers. range(start, end, step) is used, where the sequence increases by the step value13.) - What is the name given to the information that is being produced in
large quantities, rapidly and in different ways in cyberspace?14
• a) Digital Footprint
• b) Bigdata14
• c) Cyberdata
• d) Indirect information
(Big Data refers to very large and complex datasets generated rapidly in cyberspace that traditional data processing software cannot handle efficiently15.) - Identify the odd one which do not include in Digital Assets.16
• a) School Computer Lab16
• b) Software
• c) Reward point from Bank
• d) Digital Image
(Digital assets are financial assets that exist only in digital form, such as digital currencies, software, and points from online shopping17.) - Which style feature is used to bring the text in a webpage to the centre of the page?18
• a) color: #a569bd;
• b) font-family: Gentium Basic;
• c) text-align: center;18
• d) font-weight: bold;
(The instruction text-align: center; is used to align text to the centre1920.) - <h3 style="text-align:center;color:#a569bd;">Hand-made Notebooks</h3> Which cascading style is used in this line?18
- Which of the following can be used as an actuator in a robot?25
• a) IR sensor
• b) Servo motor25
• c) LED
• d) Arduino
(Actuators are components enabling automatic movement, and servo motors are an example of actuators2627.) - Analyze the code given in the figure and find the correct statements given below.28
• a) An output device is connected to Digital PIN 4.
• b) An output device is connected to Digital PIN 10.
• c) An input device is connected to Digital PIN 4.
• d) An input device is connected to Digital PIN 10.
(Note: The figure/code necessary to analyze the correct statement regarding pins 4 and 10 is not provided in the source material28.) - Which of the following planets makes it impossible to observe celestial bodies in the Stellarium software?29
• a) Mercury
• b) Venus
• c) Uranus
• d) Neptune29
(Note: The source materials do not contain information specifying which of these planets cannot be observed in Stellarium.) - Which of the following locations in the Stellarium software can be used as an observation point to view the midnight sun?29
• a) Alice Springs
• b) Kuala Lumpur
• c) Sydney
• d) Talnakh29
(The midnight sun is seen in areas beyond the Arctic and Antarctic circles3031. Talnakh, Russian Federation, is located at a high latitude (69° 29’ 11.41” N)32.) - Which of the following is an online geographic information system portal?33
• a) Quantum GIS.
• b) Grass GIS
• c) School GIS33
• d) Map Info Pro
(School GIS (https://schoolgis.nic.in/) is an online geographic information system portal34.) - Which of the following is not an open source geographic information system software?33
• a) Quantum GIS.
• b) Grass GIS
• c) Arc GIS33
• d) Map Info Pro
(Quantum GIS and GRASS are noted as free GIS software35.) - Which of the following would be an equation for drawing a line parallel to the Y axis using the input tool in GeoGebra?36
• a) x = 237
• b) y = 2
• c) x=2y
• d) y=2x
(Typing x=1 creates a line parallel to the Y-axis38.) - Which of the following constructions will be obtained if you type A(1,5) in the Input bar of GeoGebra software?37
• a) Pint (Implied: Point)37
• b) Line
• c) Circle
• d) Short line
(Typing coordinates like A(1,2) in the Input Bar creates a point A on the screen39.) - The names of some rooms (workspaces) in OpenToonz software are given. Note down their uses.4041
Name of the Room - Which one is used to distinguish the records of a table from the others?47
• a) primary key47
• b) foreign key
• c) fields
• d) private key
(The Primary Key is the field added to uniquely identify each record in a table from others4849.) - SQL means ................?47
• a) Systematic Query Language
• b) Structured Query Language47
• c) Structured Questions Language
• d) Sequenced Query Language
(SQL is the specialized computer language used by DBMSs, standing for Structured Query Language50.) - Which of the following is not an open source software license?51
• a) Apache Software License
• b) End User License Agreement52
• c) GNU General Public License
(The End-User Licence Agreement (EULA) is associated with software that provides only object code and usage restrictions, such as Microsoft Windows and Apple iOS5354.) - Which of the following is free hardware?52
• a) Apple mobile phones
• b) Arduino similar chipset52
• c) Mobile phones with Android installed
(Arduino microcontrollers are an example of hardware released under open-hardware principles51.) - What is the name given to free software?52
• a) Free software52
• b) Open software
• c) Freeware
(Free software prioritizes user freedom and knowledge dissemination5455.) - What is the shell in the GNU/Linux operating system known as?52
• a) Open Shell
• b) Linux Shell
• c) Bash52
(The shell component of the GNU/Linux operating system is called GNU Bash (GNU Bourne Again Shell)56.) - Which of the following is not an operating system?52
• a) Android
• b) Linux
• c) Unix57
(Note: All three options—Android58, Linux59, and Unix60—are discussed in the source as operating systems or based programs for operating systems57.)write without page reference numbers - Software: Free software available for graphic editing includes GIMP, Krita, Inkscape, Scribus, and LibreOffice Draw.
- Vector vs. Raster Images:
- Raster Images (e.g., JPEG, PNG) are made of pixels and may lose quality (become pixelated) when scaled.
- Vector Images (e.g., SVG, EPS) are created using mathematical equations defining lines and shapes, can be resized without losing quality, and generally have small file sizes.
- Inkscape: A Free vector graphic designing software used for high-quality designs such as logos, illustrations, posters, brochures, and typography. Its default file format is Scalable Vector Graphics (SVG), and it supports other formats like AI, PDF, and PNG.
- Poster Design Steps: Start by creating a canvas, adding text effectively, and arranging drawings, images, and shapes attractively.
- Canvas/Page Setup: In Inkscape, use File → Document Properties (shortcut: Shift + Ctrl + D) to adjust page size, units, and orientation.
- Drawing and Editing Tools (Inkscape):
- Create Rectangle & Squares (R).
- Select and Transform Objects (S) changes object size. Holding Ctrl while resizing keeps dimensions proportional.
- Colours can be applied using Fill Color (fill) or by holding Shift while selecting a colour (stroke/border).
- The Bezier Curve tool (B) is used to create regular lines and curved shapes. It helps draw complex shapes, logos, and fonts.
- Edit path by nodes (N) is used to curve or adjust lines.
- Path → Intersection is used to retain only the overlapping common part of two selected shapes.
- Align and Distribute (Shift + Ctrl + A) is used for arranging design elements with accuracy.
- Grouping objects is done using Ctrl+G.
- Opacity controls colour transparency (0% transparency means the object cannot be seen).
- The Gradient tool and Blur effect can be used to create shading and three-dimensional effects.
- Exporting: Inkscape files can be exported to PNG, JPG, and WEBP formats. For screen display, 96dpi is sufficient, while for print, 300dpi is preferred.
- Desktop Publishing (DTP): A method of preparing and printing pages using designing software on a computer. It allows a single person or team to quickly complete stages previously handled by multiple professionals (typists, graphic designers, typesetters).
- DTP Software: Scribus is a popular open-source DTP software used for designing magazines, books, and newspaper pages. Other DTP software includes LaTeX, Adobe InDesign, Microsoft Publisher, and QuarkXPress.
- Page Design Elements: In newspapers, content is often divided into columns. Design relies on images, fonts, headings, colours, arrangement of letters, and blank spaces.
- Scribus Features:
- Documents are started by selecting settings like Page Layout, size, orientation, and margin from the New Document window.
- The Shape tool is used to draw shapes, and dimensions can be entered in the Properties window.
- Node Editing allows changing the shape of figures by adjusting nodes.
- Drop Shadow adds shadow to objects.
- Text frames (T) are necessary to include and format text. Formatting options are available in the Text Properties window.
- The Line tool can be used to add lines; holding the Ctrl key ensures the line is straight.
- The Image Frame tool is used to include images. After inserting an image, it can be adjusted to the frame using Image → Adjust Image to Frame.
- QR Codes can be generated using the Barcode icon, selecting Two dimensional symbols and QR Code.
- Text can be arranged into columns using the Columns & Text Distance tab in the Text Properties window.
- The Text Overflow Icon appears at the bottom right of a text frame if the content exceeds the frame's capacity.
- To arrange images among text, adjustments must be made in the Contour Line of the image using Shape → Text flow around frame.
- Background colour can be set by drawing a large rectangle shape and using Level → Lower to bottom to place it behind the text.
- Documents are exported to PDF format using File → Export for printing.
- Career Opportunities: DTP professionals work as graphic designers, layout artists, desktop publishers, and print production specialists in various industries.
- Binary Language: Computers are electronic devices and only understand ON and OFF states, represented by the symbols 1 and 0 (binary language). These states are also known as High/Low or True/False.
- High-level Languages: Languages like Python, C, and Java that humans use to give instructions....
- Translator Programs: Convert high-level language instructions into binary language.
- Compilers: Convert instructions completely into a separate binary file (executable file) before execution (e.g., C, C++).
- Interpreters: Process and execute code line by line during execution, requiring the source code to be present (e.g., Python).
- Programming: The process of giving the necessary instructions to computers to perform a specific task.
- Algorithm: The steps for solving a problem written in a specific order.
- Python: An open-source programming language developed by Guido van Rossum in 1990, known for its simple syntax.
- Programming Basics (Python):
- Programs are typically saved with the .py extension.
- Run using the command
python3 filename.pyin the terminal. - Variables temporarily store data.
- Datatype indicates the type of data (integers, strings, etc.).
- The
input()function collects data, which is provided in text format (string). - The
int()function is used to convert data from string form to integer form so mathematical operations can be performed. - IDLE (Integrated Development Environment) is specialized software used for easily running and fixing errors in programs.
- Conditional Statements (Branching): Control the flow of the program based on whether a condition is met.
- The
if...elsestatement checks a condition. - The
if...elif...elseformat checks multiple conditions sequentially. - Syntax refers to the terminologies and rules for writing programs.
- The
- Loop Statements (Iteration): Used to repeat instructions.
whileloop: Repeats statements as long as a condition is true.forloop: Often used with therangestatement to arrange a set of numbers systematically (e.g.,range(1, 101)gives numbers 1 through 100).
- Operators: Arithmetic (+, -, *, /, %), Assignment (=), Comparison (==, >, <, >=, <=, !=), and Logical (and, or, not) are used in Python....
- The
turtlegraphics module can generate graphical output. - The command
from turtle import *adds all functions from the module. forwardis used to draw a line.right(90)orleft(90)rotates the drawing 90 degrees.- Lists store different data in a single string (e.g., colours) and can be easily iterated through using a for loop.
- Cyberspace: The virtual space where digital devices (computers, servers, phones, networks) and the information transferred between them are all linked.
- Internet: A global network of interconnected computers and physical infrastructure (servers, cables, routers). It is a component of the broader concept of cyberspace.
- Cyberworld: Specific virtual spaces within cyberspace, such as virtual reality platforms or online multiplayer games.
- Digital Footprint: The trace of information created while using the Internet (websites visited, posts shared, apps used).
- Cyber Identity: A person’s digital representation shaped by online information and activities.
- Cyber Infrastructure: Includes the Internet, hardware, network protocols, information, databases, web pages, and security systems.
- Internet of Things (IoT): A network of physical objects connected to the Internet, equipped with sensors and software to collect data and interact.
- Metaverse: An immersive platform/vast virtual world that integrates Augmented Reality (AR), Virtual Reality (VR), Artificial Intelligence (AI), and Blockchain to create an artificial world. Users are represented by Avatars.
- Digital Assets: Financial assets that exist only in
digital form and hold value (e.g., digital currencies, digital wallets,
domain names, software, points from online shopping).
- NFT (Non-Fungible Token): Valuable, proprietary digital items such as digital art, music, or rare in-game items.
- Cryptocurrency: A decentralized digital currency secured by cryptography and Blockchain technology (e.g., Bitcoin).
- Big Data: Very large and complex datasets generated
rapidly in cyberspace (e.g., from social media, e-commerce, and IoT
devices) that traditional data processing software cannot handle
efficiently.
- Explicit data collection is when a user knowingly provides information (e.g., filling forms).
- Implicit data collection gathers information without the user explicitly providing it (e.g., browsing history, location).
- Plagiarism: The act of presenting someone else's ideas, expressions, or work as your own.
- References: Details of the original sources of information used, required to acknowledge intellectual contributions.
- Reliable Sources: When searching for information, rely on sources that are authentic, reliable, and up to date. Examples include reports from scientific conferences, journals, books, and recognized agencies. Websites like www.scholar.google.com and www.semanticscholar.org help find credible scientific publications.
- Dangers of Excessive Use: Can lead to issues like FOMO (Fear of Missing Out), Gaming Disorder, Cyberchondria, Nomophobia (No Mobile Phobia), and Tech Neck. Solutions include limiting screen time and Digital Detox.
- Netiquette (Cyber Etiquette): Rules for good behaviour online, emphasizing kindness, respect, avoiding harmful messages, and not sharing other people's personal information.
- Structure: Style instructions consist of a property and its corresponding value, separated by a colon (:), and completed with a semicolon (;).
- Style Properties:
colorsets text colour;background-colorsets background colour;text-align: center;centres text; andfont-weight:adjusts font thickness. - Measurements: CSS uses absolute measurements like pixels (px), centimetres (cm), and inches (in), and relative dimensions like em and %.
- Types of Cascading Styles:
- Inline Cascading Style: Style is added directly using the
styleattribute within the opening tag of an HTML element. This leads to code repetition and complex maintenance. - Internal Cascading Style: Styles are defined once within the
<style>tag in the<head>section of the same HTML file. This is more convenient than inline style as the tag needs to be styled only once. - External Cascading Style Sheets (CSS): This method
defines styles in a separate file (saved with the .css extension) and
applies them to all required web pages. This avoids repetition across
multiple pages (like Wikipedia).
- The CSS file is linked to the HTML page inside the
<head>tag using the code:<link rel="stylesheet" type="text/css" href="filename.css">.
- The CSS file is linked to the HTML page inside the
- Inline Cascading Style: Style is added directly using the
- Cascading Style Order (Priority): If an element has multiple conflicting styles, the browser follows this priority order (highest to lowest): Inline Style > Internal Style > External Style.
- HTML Tags: The
<div>tag (Division tag) is useful for dividing the code in a webpage into different sections. - Robotics: The science that studies the design, construction, operation, and control of robots, integrating electronics, mechanical engineering, and computer science.
- Robot Functioning: Robots perceive their surroundings using sensors, analyze the information, make decisions based on instructions, and act.
- Basic Components:
- Input Devices (Sensors): Gather information (e.g., Light Sensor, IR Sensor, Microphone, Camera).
- Control Unit: Microcontrollers or Microprocessors process data and manage output (e.g., Arduino, Raspberry Pi, ESP32).
- Output Devices: Display results or perform actions (e.g., LEDs, Buzzers, Motors).
- Actuators: Components enabling automatic movement (e.g., servo motors, stepper motors).
- Arduino: An open-source hardware/software platform. The Arduino UNO board features the ATmega328P microcontroller chip. It includes DIGITAL I/O PINs (0-13) (some support PWM for controlling devices like servo motors) and Analog Input pins.
- Circuit Building: A breadboard allows building and reusing circuits without soldering.
- LED Circuits: An LED (Light Emitting Diode) must be connected with a resistor in series to prevent damage. To control the LED (e.g., blinking), it must be connected to a Digital Pin on the Arduino.
- PictoBlox Programming Modes:
- Upload Mode: The program is fully uploaded to the Arduino's memory, allowing it to run independently without the computer.
- Stage Mode: The Arduino runs based on continuous instructions received via the USB cable, requiring the computer connection.
- Signals: Instructions are given using HIGH (ON/1) and LOW (OFF/0) signals.
- Servo Motor: A motor designed to rotate only through specific angles (e.g., 0 to 180 degrees). Controlled using PWM.
- IR Sensor Module: Detects obstacles using infrared waves.
- AI and Robotics: Artificial Intelligence (AI) enables machines to imitate human intelligence. Combined with robotics, AI allows for precision tasks like manufacturing, surgery, and face recognition. The Face Detection extension in PictoBlox (used in Stage Mode) can be used for systems that recognize human faces.
- Stellarium: A free desktop planetarium software that simulates sky views and celestial phenomena.
- Setup: To observe a celestial body, one must set the Place of observation, observation time (date and time), and select the celestial body.
- Midnight Sun: To view the midnight sun, the observation location must be set to a city north of the Arctic Circle, such as Tromso, Norway.... The phenomenon, also known as White Nights, occurs during summer when the sun is visible all day without setting....
- Solstice: The Summer Solstice (June 21) is when the Sun is overhead at the Tropic of Cancer.
- Tools: The Location Window (F6) sets the place. The Date/Time Window (F5) sets the time. The Search Window (F3) finds celestial bodies. Time speed can be adjusted using Increase Time Speed (L).
- Disaster Risk Area Map: A map highlighting vulnerabilities and potential hazards, essential for planning disaster prevention and rescue operations.
- GIS Software: Records features and spatial information of the Earth's surface in layers. Used to prepare resource maps.
- Examples of GIS Software: Quantum GIS (QGIS) and GRASS are free software; Arc GIS is proprietary software. School GIS is an online portal for school information.
- QGIS Operations: Data (e.g., CSV files containing landslide details) can be added as a new layer using Layer → Add Layer → Add Delimited Text Layer. The Identify Features tool is used to view information about a specific point on the map.
- Digital Elevation Model (DEM): A 3D graphical representation of elevation data, typically stored as a raster image file (e.g., .tif).
- Slope Analysis: DEM data is used to calculate the slope of an area using QGIS Processing Toolbox → GDAL → Raster analysis → Slope. Different colours are assigned based on slope degree using the Symbology properties (Render type: Singleband pseudocolor).
- Printing: Maps are printed using the New Print Layout feature.
- GeoGebra: Interactive geometry software.
- Input Method: Geometric structures like points and lines can be created by typing commands in the Input Bar. For example,
A(1,2)creates point A.Segment(A,D)draws a line segment. - Drawing Equations: Typing equations like
x=1creates a line parallel to the Y-axis. Typingy=x^2creates a parabolic shape. Typingx^2+y^2=2creates a circle. - View: The index numbers of marked points appear in the Algebraic View.
- Persistence of Vision: The unique feature of the human eye where an image remains on the retina for a short time (one sixteenth of a second), causing sequential images viewed rapidly to be perceived as continuous motion.
- Phenakistiscope: The first device used to simulate animation (early 19th century).
- Flipbook: A type of illustrated book using a series of gradually changing images to create the feeling of movement when pages are turned continuously.
- Animation Preparation: Requires a theme, story, scenes, and a storyboard (detailed preparation of each scene). Character Design focuses on shape variation, colour selection, and modifiability.
- Animation Types: 2D animation (based on 2D images, e.g., The Jungle Book) and 3D animation (based on 3D shapes, e.g., Shrek).
- Frame Rate (FPS): The number of still images (frames) displayed per second, which determines the naturalness of the movement. A 5-second animation at 12 FPS requires 60 frames.
- OpenToonz: Free animation software used for drawing, animation, and sound.
- Workspaces (Rooms): Animation (animating position/rotation/size), Drawing (drawing/colouring/editing), and Browser.
- Xsheets: Organize animation content in columns (tracks) and frames (cells), similar to timelines.
- Vector Level: Used to draw vector images within a column.
- Tweening: A technique where the software automatically creates the changes (position, size, etc.) of an object between designated Key Frames. Position Tweening is used for movement.
- Image Sequences: Pre-prepared sequences of images can be added to frames to enable subtle movements.
- Saving and Exporting: Project files are saved with the .tnz extension. Animation is exported as a video file (e.g., MP4) using Render → Fast Render to MP4.
- Combining Scenes: Prepared scenes can be combined using video editing software like Kdenlive.
- Database: A systematic collection of tables containing interrelated information.
- DBMS: Software used to store, find, analyze, change, and eliminate information from interconnected tables.
- Table Components:
- Fields: Columns in a table (e.g., Player_Name, Total_Runs).
- Datatypes: The type of data collected in a field (e.g., Text, Number/Integer, Date, Image, Audio, Video).
- Records: Rows in a table containing all the information collected about a single entry.
- Keys:
- Primary Key (PK): A field used to uniquely identify each record in a table (e.g., Player_ID, Admission Number).
- Foreign Key: A field in one table used to establish a relationship by referring to the primary key of another table.
- DBMS Software: Important DBMS software includes Oracle, MySQL, SQL Server, and sqlite. SQLite is a free software DBMS where the database is stored as a single file.
- Structured Query Language (SQL): A specialized computer language used by DBMSs to communicate, select information, create/modify tables, and insert/edit/delete information.
- Retrieving Data: Queries are run in the Execute SQL tab.
- Example:
select Total_Runs from Player where Player_Name='Sachin Tendulkar'retrieves the total runs scored by Sachin Tendulkar. select * from Playerretrieves all details from the Player table.- Queries can join data from multiple tables by relating Foreign Keys to Primary Keys.
- Example:
- Source Code: Human-readable instructions written in a programming language; can be edited. Python programs are typically distributed as source code.
- Object Code (Executable Code): The converted machine-readable format; cannot be easily modified.
- Benefits of Open Source Code: Allows users to trust the program, learn from it, improve it, reduce bugs, lower costs, and disseminate knowledge.
- Software Publishing Platforms: GitLab, GNU Savannah, Gitea, GitHub, SourceForge are online services that help publish and manage software.
- Software License: Defines the rights granted to users regarding how the software may be used.
- GNU Public Licence (GPL): A license that ensures user freedom to use the software for any purpose, read/learn the source code, copy/edit it, and redistribute modified/unmodified versions.... GIMP is distributed under GPL.
- Free Software: Prioritizes user freedom and knowledge dissemination ("free as in liberty," not necessarily zero cost).
- Open-Source Software: Emphasizes universal accessibility, collaboration, and innovation. Examples include Apache License (used for Android OS) and BSD License.
- FLOSS: Free/Libre and Open Source Software (a middle-ground approach). Mozilla Firefox uses the Mozilla Public License (a FLOSS license).
- Proprietary Software (EULA): Software that typically provides only object code and has usage restrictions, sometimes requiring a new license for each system (e.g., Microsoft Windows, Apple iOS).
- Copyleft: A licensing method that uses copyright law to legally guarantee users the freedom to use, copy, modify, and redistribute a program.
- Richard Stallman: Founded the GNU Project in 1983 to create and make freely available software. He established the Free Software Foundation (FSF) in 1985 to support these efforts.
- GNU/Linux: The GNU Project aimed to rewrite the Unix operating system without using its code, hence the name GNU (GNU is not Unix). The GNU components were combined with the Linux kernel (created by Linus Torvalds) to form the GNU/Linux operating system. The kernel interacts directly with hardware; the shell (e.g., GNU Bash) interacts with the user.
- Development Models: Proprietary software follows the Cathedral Model; FOSS follows the Bazaar Model, relying on collaborative contribution.
- Version Control: Git (created by Linus Torvalds) is an online software used to store, manage, and track versions of software collaboratively.
- Open Hardware: A growing movement releasing hardware components under free manufacturing licenses (e.g., Arduino microcontrollers).
- A DNA nucleotide is composed of a deoxyribose sugar, a phosphate group, and a nitrogen base (Adenine, Thymine, Guanine, or Cytosine).
- An RNA nucleotide is composed of a ribose sugar, a phosphate group, and a nitrogenous base (Adenine, Uracil, Guanine, or Cytosine).
- While both share the phosphate group, they differ in two components: DNA uses deoxyribose sugar, whereas RNA uses ribose sugar; and DNA uses Thymine, whereas RNA uses Uracil.
- Co-dominance (i): Both alleles exhibit their traits at the same time (e.g., Roan coat pattern).
- Incomplete Dominance (ii): The dominant allele cannot fully hide the recessive allele, resulting in an intermediate trait.
- Dominance (iii): When contrasting traits are hybridised, only one trait (the dominant one) is expressed in the F1 generation.
- A pair of chromosomes forms a homologous chromosome, with one inherited from the mother and the other from the father. Sexual reproduction involves the transmission of factors (genes) through gametes, each gamete carrying half the genetic constitution.
- Dominance: Only the dominant trait is expressed in the F1 generation, and the recessive trait remains hidden.
- Incomplete Dominance: The F1 offspring express a trait that is intermediate to the parents because the dominant allele cannot fully hide the recessive allele (e.g., red and white flowers yielding pink flowers).
- Co-dominance: Both alleles exhibit their traits at the same time in the F1 offspring (e.g., the Roan coat pattern in cattle).
- Transcription: Messenger RNA (mRNA) is formed from the specific gene sequence in the DNA (which is in the nucleus).
- Translation: The mRNA travels to the ribosome (in the cytoplasm). Transfer RNA (tRNA) carries specific amino acids to the ribosome based on the message in the mRNA. Ribosomal RNA (rRNA), which is part of ribosomes, combines these amino acids to make the protein.
- Multiple Allelism: The gene that determines blood group in human beings has more than two alleles (specifically three alleles: Iᴬ, Iᴮ, and i).
- Co-dominance: This occurs when the alleles Iᴬ and Iᴮ are inherited together. Both alleles express their traits simultaneously, resulting in the AB blood group.
- Difference in the structure of the brain
- Influence of natural selection
Answer: - Difference in the structure of the brain: Human superiority in complex thinking is attributed to the neocortex, the cerebral cortex of the brain. In mammals, the cerebral cortex is modified into a complex, six-layered neocortex, which is more developed in humans compared to other mammals. The neocortex facilitates advanced mental processes like thinking, decision-making, learning, recalling, and social interaction.
- Influence of Natural Selection: The increase in brain capacity (which nearly tripled over two million years) is a major trend in human evolution. This development facilitated complex social behaviour, the ability to make tools, use language, and perform higher-level cognitive functions. This enhanced ability to adapt to changing environments and develop culture and advanced technologies was naturally selected, laying the foundation for the transition to Homo sapiens.
- (A) Homo habilis (iii) made tools with stones using their hands.
- (B) Homo neanderthalensis (i) buried dead bodies.
- (C) Australopithecus (iv) The skeletal structure confirms bipedalism.
- (D) Homo erectus (ii) able to walk upright on two legs.
- Only long necked giraffes survive
- Use and Disuse
- Natural selection
- Variations acquired in the life span
- Through continuous use, giraffe's neck elongates
- Inheritance of variations
- b) Opsin in rhodopsin contains retinal which is formed from vitamin A: The pigment rhodopsin (in rod cells) includes a protein (opsin) and retinal, which is formed from Vitamin A.
- d) Both rhodopsin and photopsin contain retinal: The components of both rod cell pigment (rhodopsin) and cone cell pigment (photopsin) include a protein (opsin) and retinal, formed from Vitamin A.
- Retinal - Night blindness
- Umami - Taste buds
- Cone cells - Colour Blindness
Answer: - Retinal - Night blindness: Retinal is formed from Vitamin A. Night blindness is a condition caused by the deficiency of Vitamin A.
- Umami - Taste buds: Umami is one of the main tastes recognized. Taste buds contain the chemoreceptors responsible for sensing taste.
- Cone cells - Colour Blindness: Cone cells provide vision in intense light and help in recognising colours. Colour blindness is caused by defects in the genes responsible for the production of pigments in cone cells.
- The convex lens forms a small, real, and inverted image of the object accurately on the retina. The eye adjusts the curvature of the lens to achieve the power of accommodation (focusing near/distant objects).
- Neurons (nerve cells) are specialized cells capable of receiving stimuli and forming suitable messages (nerve impulses), which are electrical signals/charges.
- Ability to See: The retina contains two types of photoreceptors:
- Rod cells: Are numerous (over 9 crores) and contain rhodopsin. They recognize objects in dim light and in shades of black and white.
- Cone cells: Are fewer (about 45 lakhs) and contain photopsin. They provide vision in intense light and help in recognizing colours.
- Evolutionary Benefit: This arrangement ensures that the organism can perceive the environment effectively across a wide range of light conditions, enabling both nocturnal and daylight activity, which is crucial for survival and adaptation.
- Conversion of Sound Waves: Sound waves are directed by the pinna into the auditory canal and vibrate the tympanum (eardrum). These vibrations are amplified and transmitted through the ear ossicles (malleus, incus, stapes) to the oval window. The oval window transmits vibrations to the fluids (perilymph and endolymph) within the cochlea. The fluid movement stimulates the hair cells located in the Organ of Corti (on the basilar membrane), generating impulses. These impulses travel through the auditory nerve to the brain, resulting in the sense of hearing.
- Effect of Damages:
- Hearing: Damage to the tympanum, ear ossicles, oval window, or the structures within the cochlea (Organ of Corti, hair cells) would impair the transmission or generation of impulses, affecting hearing.
- Balance: The vestibular system (including three semicircular canals, utricle, and saccule in the vestibule) is responsible for maintaining body balance. Damage here would inhibit the formation of impulses related to the head's linear or rotational movement, thereby impairing balance.
- Animals (Hormones): Produced by endocrine glands and transmitted to target cells through blood.
- Plants (Hormones): Produced at locations like the tip of the shoot or root, seeds, or sprouting leaves. They reach target cells via cell-to-cell transport or through xylem and phloem.
- Nervous System Role: The hypothalamus is located in the brain, functioning to maintain homeostasis (e.g., regulating body temperature, hunger, thirst). It uses neurosecretory cells to produce hormones.
- Endocrine System Role: The hypothalamus is considered the master controller of the hormone production process. It controls the functioning of most endocrine glands by regulating the production of tropic hormones secreted by the anterior lobe of the pituitary gland.
- Action of adrenal gland
- Action of the sympathetic nervous system
- Action of parasympathetic nervous system
Answer: - Action of the sympathetic nervous system (equips the body to respond during emergency situations, leading to physical changes like increased heartbeat).
- Action of the adrenal gland (medulla secretes epinephrine and norepinephrine, which prepare the body for emergency by increasing heart rate, blood pressure, and blood glucose).
- Action of parasympathetic nervous system (prepares the body to relax and perform routine functions, which happens after the danger is averted).
- Organisms belonging to the same species secrete it into the surroundings for communication.
- It is used to mark a path and to attract mates.
i) Which chemical substance is mentioned in the box?
Answer: Pheromones.
iii) How do farmers make use of this chemical substance?
Answer: Farmers utilize pheromone traps for pest control in agricultural fields. - X (Unfavourable situation): Abscisic acid (ABA) inhibits growth and maintains seed dormancy until favourable conditions arise.
- Y (Delays senescence/retains greenness): Cytokinins delay senescence and retain the green colour of leaves.
- Z (Prevents lateral bud growth): Auxins inhibit lateral bud growth.
- A person eats carbohydrate-rich food: Blood glucose level increases. Insulin production increases, which speeds up the entry of glucose into cells and accelerates the conversion of glucose into glycogen in the liver, thereby decreasing the blood glucose level.
- A person fasts for 12 hours: Blood glucose level decreases. Glucagon production increases, which accelerates the conversion of glycogen (in the liver) and amino acids (in tissues) into glucose, thereby increasing the blood glucose level.
- (d) Phagocyte approaches the pathogen.
- (b) Engulfment of pathogens in phagosome.
- (e) Phagolysosome is formed.
- (c) Enzymes destroy the pathogen.
- (a) Expulsion of waste materials.
- Eosinophil, Neutrophil
- Neutrophil, Monocyte
- Basophil, Neutrophil
- Monocyte, Lymphocyte
Answer: Neutrophil, Monocyte. - Neutrophils and monocytes are the white blood cells that participate in phagocytosis (the process of engulfing and destroying pathogens).
- Blood clotting is a mechanism that prevents blood flow and blocks the entry of pathogens into the body when a wound forms on the skin, thus functioning as an immune mechanism.
- Vaccines act as antigens.
- The immunity produced by vaccines is innate immunity.
- Vaccines help to produce antibodies against pathogens.
- All vaccines contain deactivated pathogens.
Answer: The correct statements are: - Vaccines act as antigens.
- Vaccines help to produce antibodies against pathogens.
- Antibiotic Resistance: This is a major concern where bacteria develop resistance against the drugs, making treatment complicated.
- Side Effects: Causes problems in the digestive system (diarrhoea, vomiting).
- Organ Damage: Can lead to damage to the liver and kidneys.
- Destruction of Beneficial Bacteria: Results in the destruction of beneficial bacteria that reside in the intestine.
- I. Restriction Endonuclease Enzyme is known as genetic scissors that cuts a specific gene.
- II. Ligase enzyme (genetic glue) joins two DNA segments.
- III. Plasmids (circular DNA in bacteria) are used as gene vectors.
- (IV is incorrect; the new recombinant DNA must become active in the host cell to replicate and form the desired product).
- Importance: The host cell is where the recombinant DNA (formed by ligating the desired gene into a vector, like a plasmid) is inserted. Once inserted, the genes become active, and the host cell multiplies, thereby producing the desired products (e.g., insulin).
- Limitation: If there were no host cells, the technology would be severely limited because the recombinant DNA could not be replicated, multiplied, or expressed to produce the desired products or traits in large quantities.
- CRISPR Technology: HGP data allows researchers to precisely identify the specific DNA segment (target) that needs to be cut or edited.
- Recombinant DNA Technology: HGP knowledge aids in the precise identification of desirable genes necessary to cut, ligate, and insert into vectors.
- AI in Biology: AI relies on analyzing large amounts of genetic data (Bioinformatics). HGP data enables AI to predict disease causes, suggest new treatment methods, and design personalized medicine based on an individual’s genetic makeup....
- Similarities: Both technologies fundamentally involve altering the genetic makeup of an organism. Both aim to introduce or utilize functional genes to achieve a desired outcome.
- Differences:
- Recombinant DNA Technology typically focuses on combining DNA segments from two or more organisms, often utilizing host cells (like bacteria) for large-scale production of a product (e.g., insulin).
- Gene Therapy is a specific medical application where defective genes in a patient are removed and replaced with functional genes to treat a disease.
- A (Guide RNA or gRNA): It precisely identifies the DNA segment that needs to be cut (Identifying the target).
- B (Cas9 enzyme): It acts as the genetic scissors that cuts the DNA segment identified by the guide RNA.
- Identifying the Perpetrator: DNA fingerprinting analyzes the unique sequence and pattern of nucleotides, particularly the repeated sequences in the "junk DNA" part, which vary significantly between individuals. In a forensic case, the DNA pattern obtained from the sample (hair, blood, or saliva) at the scene of the crime is compared with the DNA patterns of suspects. A match confirms the identity of the culprit.
- Identifying Dead Bodies: This technology is utilized to identify victims of accidents or disasters because an individual’s DNA pattern is unique, like a fingerprint. The unidentified body's DNA pattern can be compared to known DNA patterns of immediate family members (parents or offspring) to determine the biological relationship and thus establish the identity.
- Bioinformatics: AI analyzes large amounts of genetic data, assisting in sequencing and suggesting simplification strategies.
- Personalised Medicine: AI analyzes an individual's genetic makeup and health information to recommend the most suitable treatment regimens.
- Drug Discovery and Treatment: AI is used for discovering new drugs, predicting the effectiveness of chemical substances, and assisting in disease diagnosis and treatment recommendations.
- Transcription: Messenger RNA (mRNA) is formed from the specific gene sequence in the DNA (which is in the nucleus)13.
- Translation: The mRNA travels to the ribosome (in the cytoplasm)14.
Transfer RNA (tRNA) carries specific amino acids to the ribosome based
on the message in the mRNA14. Ribosomal RNA (rRNA), which is part of
ribosomes, combines these amino acids to make the protein14.
Question 9: How do co-dominance and multiple allelism function in the determination of blood group in the ABO blood grouping in human beings? Explain.
Answer:
• Multiple Allelism: The gene that determines blood group in human beings has more than two alleles (specifically three alleles: Iᴬ, Iᴮ, and i)4.
• Co-dominance: This occurs when the alleles Iᴬ and Iᴮ are inherited together. Both alleles express their traits simultaneously, resulting in the AB blood group4.
Question 10: All ova formed in females contain one type of sex determining chromosome. Why?
Answer: The normal genetic constitution for a female is 44 + XX15. When gametes (ova) are formed through meiosis, the pair of factors (sex chromosomes) separate10. Since both sex chromosomes are identical (X and X), every ovum produced will contain only one type of sex chromosome: the X chromosome. - Action of the sympathetic nervous system (equips the body to respond during emergency situations, leading to physical changes like increased heartbeat)6263.
- Action of the adrenal gland (medulla secretes epinephrine and norepinephrine, which prepare the body for emergency by increasing heart rate, blood pressure, and blood glucose)64.
- Action of parasympathetic nervous system (prepares the body to relax
and perform routine functions, which happens after the danger is
averted)62.
Question 7 (Abridged): Information about a chemical substance is provided in the box: * Organisms belonging to the same species secrete it into the surroundings for communication. * It is used to mark a path and to attract mates.
i) Which chemical substance is mentioned in the box? Answer: Pheromones65.
iii) How do farmers make use of this chemical substance? Answer: Farmers utilize pheromone traps for pest control in agricultural fields66.
Question 8: X, Y, and Z are the functions of different plant hormones. X: Helps to tide over unfavourable situtation; Y: Delays senescence of leaves and retains the greenness in that; Z: Prevents the growth of the lateral bud. Choose the correct option.
i) Gibberellin, Ethylene, Abscisic acid ii) Auxin, Abscisic acid, Gibberellin iii) Abscisic acid, Cytokinin, Auxin iv) Cytokinin, Gibberellin, Ethylene
Answer: iii) Abscisic acid, Cytokinin, Auxin67.
• X (Unfavourable situation): Abscisic acid (ABA) inhibits growth and maintains seed dormancy until favourable conditions arise68.
• Y (Delays senescence/retains greenness): Cytokinins delay senescence and retain the green colour of leaves69.
• Z (Prevents lateral bud growth): Auxins inhibit lateral bud growth69.
Question 9: Explain how the pancreas regulates the amount of glucose in the blood in the following situations.
Answer: The pancreas (Islets of Langerhans) regulates blood glucose using insulin (from beta cells) and glucagon (from alpha cells)70.
• A person eats carbohydrate-rich food: Blood glucose level increases71. Insulin production increases, which speeds up the entry of glucose into cells and accelerates the conversion of glucose into glycogen in the liver, thereby decreasing the blood glucose level71.
• A person fasts for 12 hours: Blood glucose level decreases71. Glucagon production increases, which accelerates the conversion of glycogen (in the liver) and amino acids (in tissues) into glucose, thereby increasing the blood glucose level72. - Vaccines act as antigens80.
- Vaccines help to produce antibodies against pathogens80.
Question 7: Analyse the table showing certain pathogens in an area and the number of people affected by them and answer the questions. (Pathogens: Naegleria fowleri 23, Leptospira 12, Plasmodium 57, Filarial worm 35)
i) Which disease affected more people in the region? Answer: Plasmodium (Malaria), with 57 infected people81.
ii) Which bacterial disease affected the people? Answer: Leptospira (Rat fever/Leptospirosis), with 12 infected people82.
iii) Which pathogen affected the residents who bathed in stagnant fresh water? Answer: Naegleria fowleri (causes amoebic encephalitis), which is mainly found in stagnant and warm fresh water83.
Question 8: Give reasons. Although antibiotics are effective medicines, their irrational use is harmful.
Answer: Unscientific and excessive use of antibiotics is harmful because it leads to several negative consequences84: - Antibiotic Resistance: This is a major concern where bacteria develop resistance against the drugs, making treatment complicated85.
- Side Effects: Causes problems in the digestive system (diarrhoea, vomiting)84.
- Organ Damage: Can lead to damage to the liver and kidneys84.
- Destruction of Beneficial Bacteria: Results in the destruction of beneficial bacteria that reside in the intestine84.
- If a pendulum takes 1 minute to complete 30 oscillations, how long does it take to complete one oscillation?
- Time for 30 oscillations = 1 minute = 60 s.
- Time for 1 oscillation = 60 s / 30 = 2 s.
- Find the number of oscillations the same pendulum completes in one second.
- Number of oscillations in 1 minute (60 s) = 30.
- Number of oscillations in 1 second = 30 / 60 = 0.5.
- If the frequency of a longitudinal wave travelling at a speed of 350 m/s in the air is 35 Hz,
- a) What is the distance between two consecutive compressions of this wave? (This distance is the wavelength λ. v=fλ, so λ=v/f).
- v=350 m/s, f=35 Hz.
- λ = 350 m/s / 35 Hz = 10 m (distance between two consecutive compressions).
- b) What about the distance between two consecutive rarefactions? (This distance is also the wavelength λ).
- Answer: 10 m.
- a) What is the distance between two consecutive compressions of this wave? (This distance is the wavelength λ. v=fλ, so λ=v/f).
- A sound wave with a frequency of 175 Hz has a wavelength of 2 m. Calculate the speed of sound.
- Speed of a wave (v) = frequency (f) × wavelength (λ).
- v = 175 Hz × 2 m.
- v = 350 m/s.
- The echo of fire cracker (kathina) is heard after 1 s by the person
who burst it. How far is the reflecting surface from the person hearing
the echo? (speed of sound in air is 350 m/s).
- Let d be the distance to the reflecting surface. Total distance travelled by the sound is 2d.
- Speed of sound (v) = (2d) / Time (t).
- d = (v × t) / 2 = (350 m/s × 1 s) / 2.
- d = 175 m. The reflecting surface will be 175 m away.
- If an ultrasonic wave emitted by a transmitter, installed on a ship
on the surface of the water, strikes a rock at the bottom of the sea and
returns after 0.2 s, what is the distance from the ship to the rock?
Consider the speed of ultrasonic waves in seawater as 1522 m/s.
- Total distance travelled = 1522 m/s × 0.2 s = 304.4 m.
- Distance from the ship to the rock = 304.4 m / 2.
- Answer: 152.2 m.
- Which of the following statements is correct?
- a) Sound and light are transverse waves.
- b) Sound and light are longitudinal waves.
- c) Sound is a longitudinal wave and light is a transverse wave.
- d) Sound is a transverse wave and light is a longitudinal wave.
- When sound passes through a medium, …………….. travels.
- (the particles in the medium / the wave / the source of sound / the medium)
- Two pith balls are suspended near the two prongs of a tuning fork
fixed on a table so as to touch the prongs. A person plays a piano
sitting near this system.
- a) In this case the pith balls move slightly. What is the reason? (forced vibration / echo)
- Answer: forced vibration
- b) While playing certain notes on the piano, the pith balls are
thrown to a maximum distance. Which phenomenon is responsible for this?
(reverberation / resonance)
- Answer: resonance
- a) In this case the pith balls move slightly. What is the reason? (forced vibration / echo)
- A ray of light from a point on an object placed in front of a lens
is depicted. F is the principal focus and 2F is the centre of curvature.
If OB = 90 cm and OI = 30 cm,
- b) Calculate the focal length of the lens.
- Given: u = −90 cm, v = +30 cm.
- Lens Equation: 1/f = 1/v - 1/u.
- 1/f = (1/30) - (1/-90) = (1/30) + (1/90) = (3+1)/90 = 4/90.
- f = 90/4 = 22.5 cm.
- b) Calculate the focal length of the lens.
- Calculate the magnification using the measurements in the figure (Figure 2.23) and write down the characteristics.
- Given: u = −90 cm, hₒ = +1.8 cm, v = +30 cm, hᵢ = −0.6 cm.
- m = hᵢ / hₒ = -0.6 / 1.8 = -1/3.
- m = v / u = +30 / -90 = -1/3.
- Characteristics: Magnification is less than one (image is smaller than the object). The negative sign indicates the image is inverted and real.
- What is the power of a concave lens of focal length 25 cm?
- Focal length of concave lens (f) = −25 cm = −0.25 m.
- Power P = 1/f.
- P = 1 / (−0.25 m).
- P = -4 D [Derived from calculation 1/0.25=4].
- A current of 0.5 A flows through a conductor with 100 Ω resistance for 5 minutes.
- a) What will be the quantity of heat produced?
- R = 100Ω, I = 0.5 A, t = 5 × 60 s = 300 s.
- H = I²Rt = 0.5 × 0.5 × 100 × 5 × 60 J.
- H = 7500 J.
- b) If a current of 1 A flows through this conductor for 5 minutes, what will be the quantity of heat produced?
- I = 1 A.
- H = 1 × 1 × 100 × 5 × 60 J.
- H = 30000 J.
- a) What will be the quantity of heat produced?
- If the resistance of a heating appliance operating at 230 V is 920 Ω, what is the quantity of heat produced in 10 minutes?
- V = 230 V, R = 920Ω, t = 10 × 60 s = 600 s.
- H = (V² / R) × t = (230 × 230 / 920) × 10 × 60 J.
- H = 34500 J.
- A heating appliance having a resistance of 92 Ω operates at 230 V.
Using various equations, calculate the heat produced by the appliance in
14 minutes and write them down in the table below.
- Given: V=230 V, R=92Ω, t = 14 minute = 840 s.
- First calculate current: I = V/R = 230/92 = 2.5 A.
- H calculation using H = I²Rt:
- H = (2.5)² × 92 × 840 J.
- H = 483000 J.
- Calculate the quantity of heat produced when a heating appliance of power 500 W operates for five minutes.
- P = 500 W.
- t = 5 min = 5 × 60 = 300 s.
- H = Pt = 500 × 300 J.
- H = 150000 J.
- Calculate the electric energy consumed if a 500 W grinder and a 600 W electric iron each operate for 2 hours.
- Total power in watt = 500 W + 600 W = 1100 W.
- Time (t) = 2 h.
- Electric energy (in kilowatt hour) = (Power in watt × time in hour) / 1000.
- E = (1100 W × 2 h) / 1000 = 2.2 kWh.
- E = 2.2 unit.
- An electric heater operating at 230 V draws 2 A current.
- a) What is the resistance of the heater?
- (Based on Ohm's Law R=V/I): R = 230 V / 2 A = 115Ω (Answer based on source formulas).
- c) What is the power of this appliance?
- (Based on P=VI): P = 230 V × 2 A = 460 W (Answer based on source formulas).
- a) What is the resistance of the heater?
- A transformer with no power loss operating at 240 V AC supplies 12 V
to an electric bell connected to it. Calculate the number of turns in
the secondary, if the primary coil of the transformer has 4000 turns.
- Given: Vₚ = 240 V, Vₛ = 12 V, Nₚ = 4000.
- Transformer Equation: Vₛ / Vₚ = Nₛ / Nₚ.
- Nₛ = (Vₛ / Vₚ) × Nₚ = (12 / 240) × 4000.
- Nₛ = 200 turns.
- A transformer with no power loss operating at an input voltage of
230 V has 120 turns in the secondary and 1200 turns in the primary. What
is the output voltage of this transformer?
- Given: Vₚ = 230 V, Nₛ = 120, Nₚ = 1200.
- Transformer Equation: Vₛ = (Nₛ / Nₚ) × Vₚ.
- Vₛ = (120 / 1200) × 230 V.
- Vₛ = 23 V (Answer based on source formulas).
- In a transformer with no power loss (Ideal transformer), the primary
has 3000 turns and the secondary has 150 turns. The primary voltage is
120 V and the current is 0.1 A. Calculate the secondary voltage and
current.
- Secondary Voltage (Vₛ):
- Vₛ / Vₚ = Nₛ / Nₚ ⟹ Vₛ = (150 / 3000) × 120 V = 6 V (Answer based on source formulas).
- Secondary Current (Iₛ):
- VₚIₚ = VₛIₛ
- Iₛ = (VₚIₚ) / Vₛ = (120 V × 0.1 A) / 6 V = 2 A (Answer based on source formulas).
- Secondary Voltage (Vₛ):
- Choose the correct answer from the brackets.
- a) What is the working principle of a generator?
- (motor principle, mutual induction, electromagnetic induction, all of these)
- b) What type of electricity is generated in the armature of a DC generator?
- (AC, DC, current at constant voltage, none of these)
- Note: Current induced in the armature is AC, rectified to DC in the external circuit.
- c) At what voltage is electricity generated in power stations in India?
- (11 kV, 11 V, 110 V, 230 V)
- d) What is the voltage of electricity supplied for household use in our state?
- (230 V, 230 kV, 11 kV, 11 V)
- a) What is the working principle of a generator?
- What is the function of the diaphragm in a moving coil loudspeaker?
- a) To amplify sound signals.
- b) To convert mechanical energy into sound waves.
- c) To separate high frequency sound signals.
- d) To increase the strength of the magnetic field.
- A transformer has 600 turns in its primary and 1800 turns in its secondary. 450 V is obtained across its secondary.
- a) which type of transformer is this?
- Since Nₛ (1800) > Nₚ (600), it is a Step-up transformer.
- a) which type of transformer is this?
- A force of 40 N was applied on a nail puller to pull a nail. If the
mechanical advantage of the nail puller was three, what would be the
load applied by the nail?
- Mechanical advantage (MA) = Load / Effort.
- MA = 3, Effort = 40 N.
- Load = Mechanical advantage × Effort.
- Load = 3 × 40 N = 120 N.
- A movable pulley is used to lift 600 N load. When the rope is pulled
8 m by applying a force of 300 N then the load raises by 4 m. Prove
that there is no gain in the work even though there is a gain in the
effort applied.
- Work done on the object (Load):
- W = F × s = 600 N × 4 m = 2400 J....
- Work done by the force applied (Effort):
- W = F₁s₁ = 300 N × 8 m = 2400 J.
- Conclusion: The work done on the object and the work done by the effort are equal. Hence we can conclude that no gain in work is achieved while using a movable pulley.
- Work done on the object (Load):
- A 600 kgwt load is lifted by 4 m along an inclined plane of length 8
m. Calculate the mechanical advantage. What force must be applied along
the inclined plane?
- Mechanical advantage (MA) of an inclined plane = length of the inclined plane / height of the inclined plane.
- MA = 8 m / 4 m = 2.
- MA = Load / Effort.
- Effort = Load / MA = 600 kgwt / 2 = 300 kgwt.
- Write down an example of a lever where the load arm and effort arm are equal. What is its mechanical advantage?
- Example: common balance.
- If the load arm and effort arm are equal, the load and the effort will be equal.
- Mechanical advantage = Effort arm / Load arm = 1.
- If a pendulum takes 1 minute to complete 30 oscillations, how long does it take to complete one oscillation?1
◦ Time for 30 oscillations = 1 minute = 60 s2.
◦ Time for 1 oscillation = 3060 s = 2 s2. - Find the number of oscillations the same pendulum completes in one second.3
◦ Number of oscillations in 1 minute (60 s) = 303.
◦ Number of oscillations in 1 second = 6030 = 0.53. - If the frequency of a longitudinal wave travelling at a speed of 350 m/s in the air is 35 Hz,4
◦ a) What is the distance between two consecutive compressions of this wave? (This distance is the wavelength λ. v=fλ, so λ=v/f)56.
▪ v=350 m/s, f=35 Hz4.
▪ λ=35 Hz350 m/s=10 m (distance between two consecutive compressions)6.
◦ b) What about the distance between two consecutive rarefactions? (This distance is also the wavelength λ)5.
▪ Answer: 10 m6. - A sound wave with a frequency of 175 Hz has a wavelength of 2 m. Calculate the speed of sound.7
◦ Speed of a wave (v) = frequency (f) × wavelength (λ)6.
◦ v=175 Hz×2 m7.
◦ v = 350 m/s7. - The echo of fire cracker (kathina) is heard after 1 s by the person
who burst it. How far is the reflecting surface from the person hearing
the echo? (speed of sound in air is 350 m/s).8
◦ Let d be the distance to the reflecting surface. Total distance travelled by the sound is 2d9.
◦ Speed of sound (v) = Time (t)2d9.
◦ d=2v×t=2350 m/s×1 s9.
◦ d = 175 m. The reflecting surface will be 175 m away.9. - If an ultrasonic wave emitted by a transmitter, installed on a ship
on the surface of the water, strikes a rock at the bottom of the sea and
returns after 0.2 s, what is the distance from the ship to the rock?
Consider the speed of ultrasonic waves in seawater as 1522 m/s.10
◦ Total distance travelled = 1522 m/s×0.2 s=304.4 m10.
◦ Distance from the ship to the rock = 2304.4 m10.
◦ Answer: 152.2 m10.
Let's Assess Questions - Which of the following statements is correct?11
◦ a) Sound and light are transverse waves.
◦ b) Sound and light are longitudinal waves.
◦ c) Sound is a longitudinal wave and light is a transverse wave.1213
◦ d) Sound is a transverse wave and light is a longitudinal wave. - When sound passes through a medium, …………….. travels.14
◦ (the particles in the medium / the wave / the source of sound / the medium) - Two pith balls are suspended near the two prongs of a tuning fork
fixed on a table so as to touch the prongs. A person plays a piano
sitting near this system.14
◦ a) In this case the pith balls move slightly. What is the reason? (forced vibration / echo)
▪ Answer: forced vibration15
◦ b) While playing certain notes on the piano, the pith balls are thrown to a maximum distance. Which phenomenon is responsible for this? (reverberation / resonance)
▪ Answer: resonance16 - A ray of light from a point on an object placed in front of a lens
is depicted. F is the principal focus and 2F is the centre of curvature.
If OB = 90 cm and OI = 30 cm,17
◦ b) Calculate the focal length of the lens.17
▪ Given: u=−90 cm, v=+30 cm17.
▪ Lens Equation: f1=v1−u118.
▪ f=u+vuv=−90+30−90×30 cm=−60−2700 cm19.
▪ f = 22.5 \text{ cm}19. - Calculate the magnification using the measurements in the figure (Figure 2.23) and write down the characteristics.20
◦ Given: u=−90 cm, ho=+1.8 cm, v=+30 cm, hi=−0.6 cm20.
◦ m=hohi=1.8−0.6=−3121.
◦ m=uv=−90+30=−3121.
◦ Characteristics: Magnification is less than one (image is smaller than the object). The negative sign indicates the image is inverted and real21. - What is the power of a concave lens of focal length 25 cm?22
◦ Focal length of concave lens (f) = −25 cm=−0.25 m23.
◦ Power P=f123.
◦ P=−0.25 m123.
◦ P = -4 \text{ D} [Derived from calculation 1/0.25=4].
Let's Assess Questions - A concave lens has a focal length of 50 cm. What will be its power?24
◦ a) +2 D b) +0.5 D c) −2 D d) −0.5 D
◦ Calculation derived from source concepts: f=−0.5 m. P=1/f=1/(−0.5)=−2 D23. - A current of 0.5 A flows through a conductor with 100 Ω resistance for 5 minutes.31
◦ a) What will be the quantity of heat produced?
▪ R=100Ω, I=0.5 A, t=5×60 s=300 s31.
▪ H=I2Rt=0.5×0.5×100×5×60 J31.
▪ H = 7500 \text{ J}31.
◦ b) If a current of 1 A flows through this conductor for 5 minutes, what will be the quantity of heat produced?
▪ I=1 A31.
▪ H=1×1×100×5×60 J31.
▪ H = 30000 \text{ J}31. - If the resistance of a heating appliance operating at 230 V is 920 Ω, what is the quantity of heat produced in 10 minutes?32
◦ V=230 V, R=920Ω, t=10×60 s=600 s33.
◦ H=RV2t=920230×230×10×60 J33.
◦ H = 34500 \text{ J}33. - A heating appliance having a resistance of 92 Ω operates at 230 V.
Using various equations, calculate the heat produced by the appliance in
14 minutes and write them down in the table below.34
◦ Given: V=230 V, R=92Ω, t=14 minute=840 s35.
◦ First calculate current: I=V/R=230/92=2.5 A35.
◦ H calculation using H = I^2 R t35:
▪ H=(2.5)2×92×840 J35.
▪ H = 483000 \text{ J}35. - Calculate the quantity of heat produced when a heating appliance of power 500 W operates for five minutes.36
◦ P=500 W36.
◦ t=5 min=5×60=300 s36.
◦ H=Pt=500×300 J36.
◦ H = 150000 \text{ J}36. - Calculate the electric energy consumed if a 500 W grinder and a 600 W electric iron each operate for 2 hours.37
◦ Total power in watt = 500 W+600 W=1100 W38.
◦ Time (t) = 2 h38.
◦ Electric energy (in kilowatt hour) =1000Power in watt×time in hour3839.
◦ E=10001100 W×2 h=2.2 kWh38.
◦ E = 2.2 \text{ unit}38.
Let's Assess Questions (Numerical problems requiring explicit calculation steps based on given values) - An electric heater operating at 230 V draws 2 A current.40
◦ a) What is the resistance of the heater?
▪ (Based on Ohm's Law R=V/I32): R=230 V/2 A=115Ω (Answer based on source formulas).
◦ c) What is the power of this appliance?
▪ (Based on P=VI41): P=230 V×2 A=460 W (Answer based on source formulas). - A transformer with no power loss operating at 240 V AC supplies 12 V
to an electric bell connected to it. Calculate the number of turns in
the secondary, if the primary coil of the transformer has 4000 turns.42
◦ Given: VP=240 V, VS=12 V, NP=400042.
◦ Transformer Equation: VPVS=NPNS42.
◦ NS=VPVS×NP=24012×400042.
◦ NS=200 turns42. - A transformer with no power loss operating at an input voltage of
230 V has 120 turns in the secondary and 1200 turns in the primary. What
is the output voltage of this transformer?42
◦ Given: VP=230 V, NS=120, NP=120042.
◦ Transformer Equation: VS=NPNS×VP42.
◦ VS=1200120×230 V42.
◦ V_S = 23 \text{ V} (Answer based on source formulas). - In a transformer with no power loss (Ideal transformer), the primary
has 3000 turns and the secondary has 150 turns. The primary voltage is
120 V and the current is 0.1 A. Calculate the secondary voltage and
current.43
◦ Secondary Voltage (V_S):
▪ VPVS=NPNS⟹VS=3000150×120 V=6 V (Answer based on source formulas).
◦ Secondary Current (I_S):
▪ VPIP=VSIS44
▪ IS=VSVPIP=6 V120 V×0.1 A=2 A (Answer based on source formulas). - Choose the correct answer from the brackets.45
◦ a) What is the working principle of a generator?
▪ (motor principle, mutual induction, electromagnetic induction, all of these)4546
◦ b) What type of electricity is generated in the armature of a DC generator?
▪ (AC, DC, current at constant voltage, none of these)
▪ Note: Current induced in the armature is AC, rectified to DC in the external circuit4748.
◦ c) At what voltage is electricity generated in power stations in India?
▪ (11 kV, 11 V, 110 V, 230 V)49
◦ d) What is the voltage of electricity supplied for household use in our state?
▪ (230 V, 230 kV, 11 kV, 11 V)49 - What is the function of the diaphragm in a moving coil loudspeaker?50
◦ a) To amplify sound signals.
◦ b) To convert mechanical energy into sound waves.51
◦ c) To separate high frequency sound signals.
◦ d) To increase the strength of the magnetic field. - A transformer has 600 turns in its primary and 1800 turns in its secondary. 450 V is obtained across its secondary.52
◦ a) which type of transformer is this?
▪ Since NS(1800)>NP(600), it is a Step-up transformer53. - A force of 40 N was applied on a nail puller to pull a nail. If the
mechanical advantage of the nail puller was three, what would be the
load applied by the nail?54
◦ Mechanical advantage (MA) = EffortLoad55.
◦ MA=3, Effort = 40 N54.
◦ Load = Mechanical advantage × Effort54.
◦ Load = 3×40 N=120 N54. - A movable pulley is used to lift 600 N load. When the rope is pulled
8 m by applying a force of 300 N then the load raises by 4 m. Prove
that there is no gain in the work even though there is a gain in the
effort applied.5657
◦ Work done on the object (Load):
▪ W=F×s=600 N×4 m=2400 J57....
◦ Work done by the force applied (Effort):
▪ W=F1s1=300 N×8 m=2400 J5759.
◦ Conclusion: The work done on the object and the work done by the effort are equal. Hence we can conclude that no gain in work is achieved while using a movable pulley.59. - A 600 kgwt load is lifted by 4 m along an inclined plane of length 8
m. Calculate the mechanical advantage. What force must be applied along
the inclined plane?60
◦ Mechanical advantage (MA) of an inclined plane = length of the inclined planeheight of the inclined plane60.
◦ MA=8 m4 m=260.
◦ MA=EffortLoad60.
◦ Effort = MALoad=2600 kgwt=300 kgwt60.
Let's Assess Questions - Write down an example of a lever where the load arm and effort arm are equal. What is its mechanical advantage?61
◦ Example: common balance62.
◦ If the load arm and effort arm are equal, the load and the effort will be equal62.
◦ Mechanical advantage = Effort armLoad arm=163.write without page reference numbers - Gene Editing involves methodologies to bring desirable changes in the genes in DNA.
- The Nobel Prize in Chemistry (2020) was shared by Emmanuelle Charpentier and Jennifer A Doudna for the discovery of CRISPR-Cas 9, a gene editing technology.
- CRISPR-Cas 9 is expected to make revolutionary advances in genetic disease therapy and cancer treatment, and can also be used to develop crops resistant to pests and diseases.
- A deeper understanding of DNA (Deoxyribonucleic acid) and genes paved the way for gene editing.
- Location: DNA is found within the chromosomes inside the cell nucleus.
- Discovery: James Watson and Francis Crick presented the double helical model of DNA in 1953, based on X-ray diffraction studies, including the crucial image 'Photo 51' taken by Rosalind Franklin.
- DNA Structure:
- It is composed of two strands.
- The strands are made up of sugar (deoxyribose) and phosphate molecules.
- The structure resembles a double helix.
- Nucleotide: This is the basic building block of DNA, composed of a deoxyribose sugar (a 5-carbon sugar), a phosphate group, and a nitrogen base.
- Nitrogen Bases: Adenine, Thymine, Guanine, and Cytosine.
- Rungs (formed by paired bases) link the strands.
- Pairing Mode: Nitrogen base pairing forms the rungs: Adenine pairs with Thymine (A-T), and Guanine pairs with Cytosine (G-C).
- Chromosome Components: DNA and histone proteins are the primary components.
- Nucleosome Formation: Eight histone proteins join to form a histone octamer. DNA strands wind around this octamer to form a nucleosome.
- Chromosome Formation: Chromosomes are formed by the packing, coiling, and recoiling of numerous nucleosomes.
- Chromatids: These are parts of a chromosome connected by a centromere.
- Human Chromosomes:
- Humans have a specific number of chromosomes.
- Somatic chromosomes: Control physical characteristics. There are twenty-two pairs of somatic chromosomes. A pair of identical chromosomes forms a homologous chromosome (one inherited from each parent).
- Sex Chromosomes: Involved in sex determination. They are X chromosome and Y chromosome.
- The Y chromosome is comparatively smaller than the X chromosome.
- The SRY gene on the Y chromosome is responsible for the development of testis in the embryo.
- Normal Genetic Constitution: Female: 44 + XX; Male: 44 + XY.
- Variant Genetic Constitutions: Examples include Turner syndrome (44+X0), Triple-X syndrome (44+XXX), Klinefelter syndrome (44+XXY), and XYY syndrome (44+XYY). These influence physical and mental development.
- Gene: A gene is a specific sequence of nucleotides in DNA. Proteins are synthesized according to gene instructions and are responsible for forming characteristics and controlling metabolic activities.
- RNA (Ribonucleic acid): Another type of nucleic acid involved in protein synthesis.
- It is made up of nucleotides containing a ribose sugar, a phosphate group, and nitrogenous bases (Adenine, Guanine, Uracil, and Cytosine).
- Most RNAs have a single strand.
- Stages of Protein Synthesis:
- Transcription: mRNA (messenger RNA) is formed from a specific nucleotide sequence (gene) in DNA, carrying messages for protein synthesis. This process takes place in the nucleus.
- Translation: tRNAs (transfer RNA) carry specific amino acids to the ribosome. rRNAs (ribosomal RNA), which are part of the ribosomes, combine amino acids to make protein. This process takes place in the cytoplasm.
- Heredity: The transmission of characteristics from parents to offspring.
- Variations: Characters expressed in offspring that differ from their parents.
- Genetics: The branch of science dealing with genes, heredity, and variation.
- Gregor Johann Mendel (Father of Genetics) laid the foundation for the field through experiments on pea plants (Pisum sativum). His conclusions are known as the Laws of Inheritance.
- Terminology:
- Factors: Hypothetical units (now known as genes) transmitted through gametes that determine a character.
- Alleles: Different forms of a gene.
- Phenotype: The observable characteristics of an organism.
- Genotype: The genetic constitution responsible for the characteristics.
- Monohybrid Cross (Single Trait):
- Inference: When a pair of contrasting traits is hybridised, only one (the dominant trait) is expressed in the first generation (F1), while the other (recessive trait) remains hidden. The hidden trait reappears in the second generation (F2).
- Law of Segregation: When gametes are formed, the factors (alleles) that determine the trait get separated without mixing.
- The ratio of dominant to recessive traits in the F2 generation is 3:1.
- Dihybrid Cross (Two Traits):
- Mendel’s Postulate (Law of Independent Assortment): When two or more different traits are combined, each trait is inherited independently to the next generation without mixing; one pair of alleles does not influence the separation of another pair.
- Non-Mendelian Inheritance: Explains traits
resulting from complex interactions among genes, environment, and other
factors, limiting the explanation provided solely by Mendel’s laws.
- Incomplete Dominance: A dominant allele cannot fully hide the recessive allele. The offspring expresses a character intermediate to the parents (e.g., pink flowers from red x white).
- Co-dominance: Both alleles exhibit their traits at the same time. The F1 generation shows similarity with both parents (e.g., Roan coat pattern, ABO blood group).
- Multiple Allelism: The gene that determines a character has more than two alleles (e.g., ABO blood group determined by IA, IB, and i).
- Polygenic Inheritance: More than one gene controls the character (e.g., difference in skin colour).
- Genetic Processes Responsible for Variations:
- Crossing Over: Occurs during the first phase of meiosis. Homologous chromosomes pair up. Chromatids break at the point of contact (chiasma) and exchange segments, causing a recombination of alleles. This leads to the appearance of new traits in the offspring.
- Mutation: A sudden, heritable change in the genetic constitution of an organism. It can be caused by errors during DNA replication, exposure to certain chemicals, or radiations. Mutations change genes, are transferred through generations, and play a crucial role in evolution.
- Antibiotic Resistance: Resistance in bacteria (e.g., tuberculosis bacteria) is caused by a mutation in a specific gene. The mutated bacteria multiply even in the presence of antibiotics. Over time, through further mutations, they acquire the ability to resist multiple antibiotics, leading to multi-drug-resistant strains (superbugs).
- Lamarckism (Theory of Inheritance of Acquired Characters): Initiated by Jean Baptiste Lamarck.
- Idea: Organisms adapt to changes, and characters acquired during their lifetime (e.g., giraffe stretching its neck to reach high leaves) are transmitted through generations, leading to the emergence of new species.
- Limitation: Later scientists proved that acquired characters do not impart change in the genetic structure of organisms and are thus not inherited.
- Darwinism (The Theory of Natural Selection): Proposed by English naturalist Charles Darwin. It marked the foundation for modern evolutionary perspectives and was published in On the Origin of Species (1859).
- Key Concepts of Natural Selection:
- Over Production: Organisms produce more offspring than the environment can support.
- Variations: Organisms exhibit differences (size, immunity, etc.) that can be favourable or harmful.
- Struggle for existence: Competition among organisms due to limited resources (food, shelter, mates).
- Survival of the fittest: Organisms with favourable variations survive the struggle, reproduce more effectively, and produce new generations.
- Natural Selection: Favourable variations are passed on and accumulate over time, leading to the creation of new species that cannot reproduce within the original species.
- Neo Darwinism: A rationalised theory developed after incorporating discoveries of Gregor Mendel and concepts of chromosomes and genes. It recognized that the causes of variation are genetic changes, genetic recombination during sexual reproduction, and gene flow.
- Speciation: The process in which new species arise from a common ancestor.
- LUCA (Last Universal Common Ancestor): Thought to be the ancestor of all species.
- MRCA (Most Recent Common Ancestor): The ancestor shared by different species.
- Speciation occurs when members of a population become isolated (by ecological or other factors like mutation/natural selection), accumulate variations over time, and eventually become unable to reproduce mutually.
- Evidences of Evolution:
- Molecular Biology: Comparing the sequence of nucleotides in DNA or amino acids in proteins. For example, the beta chain of haemoglobin shows 0 difference between humans and chimpanzees, suggesting the closest evolutionary relationship.
- Comparative Anatomy: Similarities in the internal structure of different organisms validate evolution. Homologous structures, like the forelimbs of humans, cats, whales, and bats, are similar internally but differ in external structure and function.
- Fossil Evidences: Remains or traces of ancient organisms. They show that organic evolution is a gradual process (e.g., ancestors of horses had shorter legs) and reveal connecting links (e.g., Archaeopteryx possessing features of both reptiles and birds).
- Primate Characteristics: Humans, monkeys, and apes belong to the group of primates. Common features include a thumb that can be opposed to other fingers and binocular vision.
- Evolutionary Trend: A major trend in human evolution is the increase in brain capacity, which nearly tripled over two million years. This enabled complex social behaviour, tool making, language use, and higher-level cognitive functions.
- Key Ancestors (with Cranial Capacity):
- Sahelanthropus tchadensis (350 cm³): First link in human evolutionary series.
- Astralopethecus (450 cm³): Skeletal structure confirms bipedalism (walking on two legs).
- Homo habilis (600 cm³): Made tools with stones using hands....
- Homo erectus (900 cm³): Able to walk upright on two legs; used excellent stone weapons....
- Homo neanderthalensis (1450 cm³): Contemporaries of modern man; buried dead bodies....
- Homo sapiens (1350 cm³): Modern man; acquired technology, agriculture, built cities.
- Role: The nervous system controls and coordinates the vital functions of the body.
- Components: Brain, spinal cord, nerves, and receptors.
- Neuron (Nerve Cells): Basic building blocks; specialised cells capable of receiving stimuli and forming messages.
- Cell body (Cyton): Center of the neuron.
- Dendrites/Dendrons: Fine fibres/branches that receive messages from adjacent neurons and transmit them to the cyton.
- Axon: The longest fibre from the cell body.
- Axonites: Branches of the axon.
- Synaptic knob: Knob-like structure at the tip of the axonite; contains a neurotransmitter (e.g., Acetylcholine) to transfer chemical messages.
- Neuroglial cells: More than half of the brain and spinal cord cells. They cannot receive stimuli or transmit messages. Functions include bringing nutrition, eliminating wastes, and acting as defence cells.
- Myelin Sheath: A layer covering some axons, made up of shiny white fat (Myelin).
- Functions: Increases the speed of message transmission (acts as an insulator), provides nourishment, and protects the axon.
- Formation: Produced by oligodendrocytes (in brain/spinal cord) and Schwann cells (in nerves).
- Matter: White matter is where myelinated neurons are abundant; grey matter is where cell bodies and parts without myelin sheath are seen.
- Protection of CNS (Brain and Spinal Cord):
- Covered by the three-layered Meninges.
- Cerebrospinal Fluid (CSF): Fills the space between the inner membranes of the meninges, the brain cavities, and the central canal of the spinal cord. Functions include providing oxygen/nutrients, eliminating wastes, regulating pressure, and protecting from external injuries.
- Divisions of Nervous System:
- Central Nervous System (CNS): Includes the Brain and Spinal cord.
- Peripheral Nervous System (PNS): Includes 12 pairs of cranial nerves and 31 pairs of spinal nerves, receptors, and nerve ganglia.
- Brain Functions:
- Cerebrum: Largest part. Centre of memory, intelligence, thinking, imagination, and voluntary movements.
- Cerebellum: Second largest part; maintains equilibrium by coordinating muscular activities.
- Thalamus: Acts as the relay station of messages to and from the cerebrum.
- Hypothalamus: Helps in maintaining homeostasis by regulating body temperature, hunger, thirst, and emotions.
- Medulla Oblongata: Controls involuntary activities like heartbeat, ventilation, vomiting, cough, and sneezing.
- Nerve Impulse Transmission: Messages are transmitted as nerve impulses.
- Unstimulated neuron: Outer surface is positively charged; inner surface is negatively charged.
- Stimulation: Positive ions enter the cell, causing a temporary charge variation.
- Synapse: The part where an impulse is transferred from one neuron to another.
- The synaptic knob secretes neurotransmitters into the synaptic cleft (gap), which bind to the receptors of the post-synaptic membrane, stimulating the next neuron.
- Synapses transmit impulses in only one direction and increase their speed.
- Neocortex: The complex, six-layered cerebral cortex, highly developed in humans. Its synapses enable advanced mental processes like thinking and decision-making.
- Types of Neurons (by function):
- Sensory neuron: Transmits impulses from receptors to CNS.
- Motor neuron: Transmits instructions from CNS to organs (muscles/glands).
- Inter neuron: Found between neurons, helping in central processing.
- Autonomous Nervous System (ANS): Part of the PNS that regulates body activities by itself.
- Sympathetic system: Prepares the body for emergency situations (e.g., dilates pupil, increases heartbeat).
- Parasympathetic system: Prepares the body to relax and perform routine functions (e.g., constricts pupil, decreases heartbeat, stimulates digestion).
- Reflex Actions: Reactions that occur spontaneously
and involuntarily in response to stimuli. They can originate from the
spinal cord or the brain.
- Reflex Arc: The pathway through which impulses are transmitted: Receptor → Sensory neuron → Inter neuron (often in spinal cord) → Motor neuron → Muscle/Gland.
- Stimuli: Circumstances that lead to responses in living beings (external or internal).
- Sensory Receptors: Specialised cells or nerve endings that recognise stimuli.
- Impulse Formation: Stimuli cause electrical impulses called Receptor potential. If the concentration of these impulses is high, Action potential is formed in the associated neurons, which travels as a nerve impulse.
- Types of Senses:
- General Senses: Detected by receptors in skin, muscles, joints, internal organs (e.g., touch, pain, heat, pressure).
- Special Senses: Detected by receptors concentrated only in certain organs (e.g., vision, hearing, taste, smell).
- Protective Mechanisms: Eyelid, eyelashes, tears. Tears are produced by lacrimal glands and contain the enzyme lysozyme to protect from infections.
- Conjunctiva: A membrane covering the anterior part of the eye (except cornea); keeps it moist and lubricated.
- Layers of the Eye:
- Sclera (Outer Layer): Provides firmness and protection.
- Choroid (Middle Layer): Provides oxygen and nutrients to the retina; regulates temperature. Contains the Iris.
- Retina (Inner Layer): Contains photoreceptor cells; where the image is formed.
- Associated Parts:
- Cornea: Transparent anterior part; allows light to enter.
- Iris: Contains melanin pigment; regulates the amount of light entering the eye by adjusting the size of the Pupil (the aperture at its centre)....
- Lens: A convex lens that forms a small, real, and inverted image on the retina. Attached to Ciliary muscles by ligaments.
- Power of Accommodation: The ability of the eye to focus images of both near and distant objects accurately on the retina by changing the curvature of the lens.
- Eye Chambers and Humors:
- Aqueous chamber: Between cornea and lens; contains watery Aqueous humor (provides O₂/nutrients to lens/cornea, regulates pressure).
- Vitreous chamber: Between lens and retina; contains jelly-like Vitreous humor (maintains the shape of the eyeball).
- Photoreceptors (in Retina): Both types contain pigments composed of opsin and retinal (formed from Vitamin A).
- Rod Cells: More numerous (9+ crores); contain Rhodopsin. Recognise objects in dim light and shades of black and white.
- Cone Cells: Less numerous (45 lakh); contain Photopsin. Provide vision in intense light and help recognise colours.
- Vision Centre: The yellow spot (macula) is where cone cells are abundant. The blind spot is where the optic nerve originates, lacking photoreceptors.
- Impulse Transmission: In the dark, photoreceptors continuously produce the neurotransmitter Glutamate. In the presence of light, glutamate production stops, activating 'on bipolar cells' which send impulses via ganglion cells to the optic nerve.
- Binocular Fusion: The brain compares the two slightly different images received from both eyes and combines them, resulting in 3D vision and depth perception.
- Disorders: Short-sightedness (enlarged eyeball), Cataract (opaque lens), Glaucoma (increased pressure due to failure of aqueous humor reabsorption), Night blindness (Vitamin A deficiency).
- Main Parts: Outer ear, Middle ear, Inner ear.
- Outer Ear: Pinna (directs sound waves) and Auditory canal (protects tympanum, contains hair/wax).
- Middle Ear: Tympanum (eardrum) vibrates with sound. Ear ossicles (Malleus, Incus, Stapes) transmit vibrations. Eustachian canal connects to the pharynx and balances air pressure on both sides of the tympanum.
- Inner Ear: Includes the Cochlea (hearing) and the Vestibular system (balance).
- Mechanism of Hearing:
- Vibrations travel from the tympanum → ear ossicles → oval window.
- Cochlea: Snail-shaped, has three chambers. Upper/lower chambers contain Perilymph; middle chamber contains Endolymph.
- Organ of Corti: Located in the basilar membrane. Contains auditory receptors (hair cells) that generate impulses when vibrated. Impulses reach the brain through the auditory nerve.
- Mechanism of Balance:
- Involves the vestibular system in the inner ear: three semicircular canals and the vestibule (containing utricle and saccule).
- Endolymph moves with head rotation, stimulating hair cells in the canals and vestibule.
- Impulses travel through the vestibular nerve to the brain (cerebellum).
- Hearing Impairment: Caused by noise intensity above 80 decibels; loud noise (>85 dB) for a short time or less intense noise (<55 dB) for a very long time can cause permanent impairment.
- Olfaction (Smell):
- Particles responsible for smell dissolve in the mucus produced by the mucus membrane in the nasal cavity.
- Millions of olfactory neurons (receptors) get stimulated.
- Impulses travel through the olfactory nerve to the brain.
- Taste:
- Detected by Chemoreceptors located in Taste buds, which are found in the Papilla of the tongue.
- Substances dissolve in saliva and stimulate the chemoreceptors.
- Main tastes recognised: sweet, sour, salty, pungent, bitter, and umami.
- Skin Receptors (Touch/Pain): The skin contains various specialised receptors.
- Nocireceptors (Independent nerve endings): Specialised receptors that identify pain.
- Merkel disc/Meissner corpuscles: Detect touch and pressure.
- Pacinian corpuscles: Detect vibration and high-frequency touch.
- Definition: Hormones are chemical substances that regulate and coordinate body functions alongside the nervous system.
- Target Cells: A cell in which a hormone acts. Each target cell has receptors suitable for that hormone.
- Mechanism: Hormones combine with receptors to form a hormone-receptor complex, which controls activities inside the cell.
- Transport: Animal hormones (from endocrine glands) reach target cells through the blood. Plant hormones move via cell-to-cell transport or through xylem/phloem.
- Auxin: Discovered by F W Went. Stimulates cell elongation, increases stem length, inhibits lateral bud growth, and regulates tropic movements. Tends to stay away from light, causing bending (phototropism).
- Gibberellins: Break seed dormancy; influence fruit and seed growth; stimulate cell division in stems and roots.
- Cytokinins: Stimulate cell division and differentiation; stimulate lateral bud growth; delay senescence and retain the green colour of leaves.
- Ethylene: Plays a role in the ageing of leaves/flowers and the ripening of fruits.
- Abscisic Acid (ABA): Inhibits the growth of plant parts; maintains seed dormancy until favourable conditions arise; enables plants to tide over unfavourable conditions.
- Photoperiodism: The response of plants to the duration of day and night, regulating flowering time. Involves Phytochrome, a light-sensitive pigment synthesized in fully developed leaves.
- Thyroid Gland (Metabolism):
- Thyroxine (from Follicular cells): Controls metabolism, body temperature, brain development in children, and maintains health of heart/skin/reproductive system.
- Calcitonin (from Parafollicular cells): Reduces the level of calcium in the blood.
- Disorders: Hyperthyroidism (excessive thyroxine), Hypothyroidism (reduced thyroxine), and Goitre (swelling in the neck).
- Regulation of Calcium (Normal: 9-11 mg/dL): Maintained by the combined action of Calcitonin and Parathormone (from the parathyroid gland).
- When calcium is high, Calcitonin inhibits its release from bones.
- When calcium is low, Parathormone stimulates its release from bones and increases reabsorption from the blood.
- Pancreas (Glucose Regulation):
- Islets of Langerhans: Contain Alpha cells (produce Glucagon) and Beta cells (produce Insulin).
- Insulin Action (when glucose level increases): Speeds up glucose entry into cells; promotes glucose → glycogen conversion in the liver.
- Glucagon Action (when glucose level decreases): Promotes glycogen → glucose conversion in the liver; promotes glucose synthesis from amino acids.
- Diabetes Mellitus: Blood glucose level rises above normal (FBS > 126 mg/dL). Type 1 (loss of insulin production due to beta cell destruction). Type 2 (variation in insulin production or decreased effectiveness).
- Adrenal Gland (Emergency): Works with the sympathetic nervous system.
- Medulla: Secretes Epinephrine (adrenaline) and Norepinephrine. These increase heart rate/blood pressure/blood glucose, preparing the body for emergency.
- Cortex: Produces corticosteroids (Glucocorticoids like Cortisol, Mineralocorticoids like Aldosterone, and Gonadocorticoids).
- Cortisol resists inflammation, suppresses immune responses, and maintains glucose homeostasis.
- Pineal Gland (Sleep): Produces Melatonin. Variations in secretion influence sleep and wakefulness; the gland is known as the biological clock.
- Hypothalamus and Pituitary (Master Control):
- Hypothalamus: Master controller. Controls pituitary function by producing Releasing and Inhibitory hormones that regulate tropic hormone production in the anterior lobe.
- Pituitary Anterior Lobe: Secretes tropic hormones (TSH, ACTH, GTH) and Somatotropin (GH) (growth hormone).
- Pituitary Posterior Lobe: Stores and secretes Vasopressin (ADH) (water reabsorption in kidney) and Oxytocin (smooth muscle contraction, lactation).
- Growth Disorders: Caused by Somatotropin variations. Dwarfism (decreased GH during growth phase), Gigantism (increased GH during growth phase), Acromegaly (increased GH after growth phase).
- Pheromones: Chemical substances secreted by organisms into the surroundings for communication with the same species. Examples include: Territorial, Aggregation, Alarm, Trail, and Sex pheromones.
- Health: A complete state of physical, mental, and social well-being.
- Antigen: Anything (pathogens, pollen, chemicals) that enters the body and causes disease.
- Immunity: The body's ability to prevent the entry of pathogens and destroy those already inside.
- Innate Immunity (Non-specific): Natural, present by birth, acts irrespective of the type of pathogen.
- Primary Level: Physical and chemical barriers (e.g., Lysozyme in tears/saliva, Mucus membrane, HCl in stomach, Wax in ear).
- Secondary Level: Defence mechanisms if pathogens enter:
- Phagocytosis: Phagocytes (e.g., Neutrophils and Monocytes) engulf and destroy pathogens.
- Inflammatory Response: Blood vessels dilate due to histamine release; increased blood flow brings white blood cells to the injured area.
- Fever: Increased body temperature (above 98.6°F) triggered by pyrogens. It enhances phagocytosis and inhibits pathogen growth.
- Blood Clotting: Prevents blood loss and blocks pathogen entry. Involves thromboplastin converting prothrombin to thrombin, and thrombin converting fibrinogen to fibrin threads.
- Acquired Immunity (Specific): Develops after birth; specifically recognises antigens. Carried out by Lymphocytes.
- T Lymphocytes: Form in bone marrow, mature in the thymus gland. Destroy infected cells and cancer cells.
- B Lymphocytes: Form and mature in the bone marrow. Produce proteins called antibodies.
- Innate Immunity (Non-specific): Natural, present by birth, acts irrespective of the type of pathogen.
- Artificial Immunity (Vaccination): Immunisation is an artificial method to prepare immune cells.
- Vaccines: Act as antigens, stimulating the immune system to produce antibodies for long-term protection. Edward Jenner is known as the father of vaccination.
- Acquired Diseases: Occur during life (communicable or non-communicable).
- Transmission: Direct contact, contaminated food/water, surfaces, coughing/sneezing (droplets).
- Bacterial Diseases: Bacteria release toxins or enzymes that destroy host tissues. Examples: Rat fever (Leptospira), Tuberculosis (Mycobacterium tuberculosis).
- Viral Diseases: Viruses multiply using the host cell's genetic mechanism, destroying the cells. Examples: AIDS (HIV attacks T lymphocytes, reducing immunity), Nipah.
- Fungal Diseases: Fungi infect skin/nails or produce toxins. Examples: Ringworm, Candidiasis.
- Protozoan Diseases: Unicellular eukaryotes. Example: Malaria (Plasmodium, transmitted by Anopheles mosquito, destroys red blood cells). Amoebic encephalitis (Naegleria fowleri).
- Worm Infestations: Caused by parasitic worms (e.g., pin worm, round worm). Filariasis is caused by filarial worms transmitted by Culex mosquitoes, which lodge in lymphatic vessels and cause swelling.
- Non-Contagious Diseases:
- Cancer: Abnormal and uncontrolled cell division. Normal cells turn into cancer cells when control mechanisms fail, spreading through blood/lymph.
- Hereditary Diseases (Genetic Defects): Sickle cell anaemia (defective gene for haemoglobin, causes sickle-shaped RBCs). Haemophilia (defective gene for blood clotting proteins).
- Treatment Systems: Ayurveda (traditional Indian system, focus on balance, diet, herbs). Homeopathy (uses diluted doses of natural substances). Modern Medicine (focus on diagnosis, pathogens, surgery, organ transplantation).
- Antibiotics: Medicines used against bacteria, derived from microorganisms or synthesized. Revolutionary (Penicillin discovered by Alexander Fleming, 1928). Excessive use leads to side effects and Antibiotic resistance.
- Blood Groups: Determined by the presence of A antigen and B antigen on the surface of RBCs.
- Rh factor: Determined by the presence (positive) or absence (negative) of the D antigen.
- Blood group matching is essential for transfusion because antibodies in the recipient's plasma may act against donor antigens, causing agglutination.
- Biotechnology: Technology using living things or their parts to provide useful products and services for humans.
- Genetic Engineering: Technology used for creating desired traits in organisms by combining or deleting genes.
- Recombinant DNA Technology: Combines DNA segments from two or more different organisms. Requires:
- Restriction Endonuclease Enzyme: Acts as genetic scissors, cutting specific genes.
- Ligase Enzyme: Acts as genetic glue, joining DNA segments.
- Vector: Carries genes (e.g., bacterial plasmids or some viruses).
- Host Cell: Where the recombinant DNA is inserted and becomes active (e.g., production of human insulin using bacteria).
- CRISPR Technology (Gene Editing): Modern technology used to edit DNA with great precision.
- Uses Cas9 enzyme as scissors to cut DNA.
- Uses a Guide RNA (gRNA) that precisely identifies the DNA segment to be cut.
- Allows removal of unwanted characteristics or addition of new ones.
- Genetically Modified Organisms (GMOs): Plants, animals, or microorganisms whose genetic constitutions have been altered through genetic engineering. Examples include Bt. Cotton (pest resistance), Golden rice (nutrient-enriched), and E. coli (insulin production).
- Genome: The sum total of all the genetic materials in an organism.
- Human Genome Project (HGP): A global initiative (1990–2003) to sequence and understand the human genome (approximately 300 crore DNA base pairs). It used Gene Mapping to identify gene locations.
- HGP Findings: Humans have 20,000 to 25,000 genes; only 1–2% of the genome consists of functional genes.
- Gene Therapy: The method of treating diseases by removing defective genes and replacing them with functional genes.
- Somatic gene therapy: Delivers healthy genes to body cells; genetic changes are not passed on to the next generation.
- Germline gene therapy: Transfers genes into reproductive cells; genetic changes are transmitted to future generations (raises ethical questions).
- DNA Fingerprinting: Discovered by Sir Alex Jeffrey (1984).
- Basis: While 99.9% of DNA is the same, variations in the remaining 0.1% (especially in repeated sequences in non-coding regions) are unique to each individual.
- Uses: To identify culprits, determine biological relationships (parents/offspring), identify genetic disorders, and track endangered species.
- Human Microbiome Project (HMP): Launched in 2007,
studying the collection of microorganisms (bacteria, fungi, viruses) and
their genes that inhabit the human body. This community provides
services like immunity, digestion, and vitamin production.
- Faeces to Medicine: Beneficial bacteria collected from healthy faeces ("poop pills") are used to treat drug-resistant bacterial infections.
- Biology and Artificial Intelligence (AI): AI plays a major role in biological study.
- Applications: Diagnosis, drug discovery, personalised medicine (analysing genetic makeup), improving agriculture (monitoring soil/predicting crop diseases), pollution prediction, and genome sequencing.
- Bioinformatics: A scientific discipline that analyses large amounts of biological data by combining computer science, mathematics, and statistics.
- Technologies for Environmental Conservation:
- Cryopreservation: Preserving living cells/tissues at very low temperatures (-196°C) for long-term preservation.
- Bioremediation: Uses microorganisms and plants to remove pollutants from contaminated environments.
- Wildlife Tracking/Data Sensors: Utilising sensors and satellite remote sensing to monitor biodiversity and animal movement for conservation planning.
- Chain Isomers: Hexane (C₆H₁₄) and 2,3–Dimethylbutane (C₆H₁₄). (Pair b and f).
- Position Isomers: Propan–1–ol (C₃H₈O) and Propan–2–ol (C₃H₈O). They have the same functional group but differ in its position. (Pair c and e).
- Functional Isomers: (Based on common molecular formulae for functional isomers: C₃H₈O corresponds to Propan-1-ol, Propan-2-ol, and Methoxyethane (CH₃−O−CH₂−CH₃).)
- Metamers: Methoxypropane (CH₃−O−CH₂CH₂CH₃, C₄H₁₀O) and Ethoxyethane (CH₃CH₂−O−CH₂CH₃, C₄H₁₀O). (Pair a and d).
- For 3f: n=3. The maximum possible value for l is (3−1)=2 (representing s,p,d). Since l=3 corresponds to the f subshell, 3f is not possible.
- For 2d: n=2. The maximum possible value for l is (2−1)=1 (representing s,p). Since l=2 corresponds to the d subshell, 2d is not possible.
- H₂: Molar Mass = 2×1=2. Moles = 112/22.4=5. Given Mass = 5×2=10.
- CO₂: Molar Mass = 12+2(16)=44. Moles = 440/44=10. Volume = 10×22.4=224.
- NH₃: Molar Mass = 14+3(1)=17. Moles = 340/17=20. Volume = 20×22.4=448.
- Zinc sulphide : Roasting :: Calcium carbonate : Calcination.
- Magnetite : Magnetic separation :: Bauxite : Leaching.
- The ore is treated with hot NaOH solution.
- Electricity is used as the reducing agent to extract the metal.
(i) These facts are related to the production of which metal?
(ii) What is the reason for using electricity as the reducing agent?
(iii) Which substance is used as the electrolyte here?
(iv) Which gas is liberated at the anode?
Answer:
(i) The metal is Aluminium.
(ii) Aluminium is a highly reactive metal (and forms stable compounds). Strong reducing agents (like electrolysis) are required to extract highly reactive metals.
(iii) The electrolyte is anhydrous Alumina (Al₂O₃) dissolved in molten Cryolite (Na₃AlF₆).
(iv) Oxygen gas (O₂) is liberated at the anode. - The compounds should be soluble in water.
- The elements present in the compounds must be easily available to plants.
- The compounds must be stable and remain in the soil for a long time.
- They should not cause significant variations to the pH of the soil.
- They should not be toxic to plants.
- (i) Correct (KCl is formed from Strong Acid (HCl) + Strong Base (KOH), hence neutral).
- (ii) Correct (Formed from Strong Acid (H₂SO₄) + Weak Base (NH₄OH), hence acidic).
- (iii) Incorrect (AlCl₃ is formed from Strong Acid (HCl) + Weak Base (Al(OH)₃), hence acidic).
- (iv) Correct (Formed from Weak Acid (CH₃COOH) + Strong Base (NaOH), hence basic, increasing basicity).
The correct statements are (i), (ii), and (iv). - Chain Isomers: Hexane (C6H14) and 2,3–Dimethylbutane (C6H14)1516. (Pair b and f).
- Position Isomers: Propan–1–ol (C3H8O) and Propan–2–ol (C3H8O). They have the same functional group but differ in its position14. (Pair c and e).
- Functional Isomers: Propan–1–ol (C3H8O) and Ethoxyethane (C4H10O) – Note: These are NOT isomers based on molecular formula. (Based on common molecular formulae for functional isomers: C3H8O corresponds to Propan-1-ol, Propan-2-ol, and Methoxyethane (CH3−O−CH2−CH3).)
- Metamers: Methoxypropane (CH3−O−CH2CH2CH3, C4H10O) and Ethoxyethane (CH3CH2−O−CH2CH3, C4H10O). (Pair a and d)78.
- Ores are less dense than the impurities.
- The compounds should be soluble in water106.
- The elements present in the compounds must be easily available to plants106.
- The compounds must be stable and remain in the soil for a long time107.
- They should not cause significant variations to the pH of the soil107.
- They should not be toxic to plants107.
II. Let us assess108...
Question 1108: Chemical formula of certain salts are given below: KCl,(NH4)2SO4,AlCl3,CH3COONa. Choose the correct statements. (i) KCl does not undergo hydrolysis. (ii) (NH4)2SO4 is an acidic salt. (iii) AlCl3 is a basic salt. (iv) CH3COONa is used to increase the basicity of an aqueous solution.
Answer:
• (i) Correct (KCl is formed from Strong Acid (HCl) + Strong Base (KOH), hence neutral)114115.
• (ii) Correct (Formed from Strong Acid (H2SO4) + Weak Base (NH4OH), hence acidic)114116.
• (iii) Incorrect (AlCl3 is formed from Strong Acid (HCl) + Weak Base (Al(OH)3), hence acidic)114116.
• (iv) Correct (Formed from Weak Acid (CH3COOH) + Strong Base (NaOH), hence basic, increasing basicity)114117. The correct statements are (i), (ii), and (iv)108.
Question 4109110: Explain with chemical equations of the chemical reactions that take place in the left and right chambers of the membrane cell during the chlor-alkali process.
Answer: This process involves the electrolysis of concentrated aqueous sodium chloride solution (brine)118.
Chamber - Main Chain Selection: The longest chain containing the maximum number of carbon atoms is the main chain; the remaining atoms or groups are considered branches.
- Numbering: Carbon atoms must be numbered so that the carbon atom carrying the branch receives the lowest position number.
- Alkyl Groups: Small branches are called alkyl groups, formed when a hydrogen atom is removed from a saturated hydrocarbon (e.g., Methyl (−CH₃), Ethyl (−CH₂−CH₃)).
- IUPAC Name Format (Single Branch): Position number of branch + hyphen + name of alkyl group + word root + suffix (ane) (e.g., 2–Methylpentane).
- Multiple Branches:
- If the same branch appears more than once, prefixes like di (two), tri (three), or tetra (four) are used. Position numbers are separated by commas. (e.g., 2,5–Dimethylheptane).
- If numbering from either end gives the same position number for the first branch, numbering should be done to give the second branch a lower position number.
- If a carbon atom has two identical branches, their position numbers must be repeated (e.g., 2,2–Dimethylpropane).
- Alkenes (Double Bond): Word root + hyphen + position of double bond + hyphen + suffix ('ene') (e.g., But–1–ene, Pent–2–ene)....
- Alkynes (Triple Bond): Word root + hyphen + position of triple bond + hyphen + suffix ('yne') (e.g., But–1–yne, But-2-yne).
- Chain Isomerism: Isomers that have the same molecular formula but differ in the structure of the carbon chain.
- Position Isomerism: Isomers that have the same molecular formula and the same functional group, but differ in the position of the functional group (this also applies to the position of double or triple bonds).
- Functional Isomerism: Compounds that have the same molecular formula but different functional groups (e.g., Ethanol (CH₃CH₂OH) and Methoxymethane (CH₃−O−CH₃)).
- Metamerism: Isomerism exhibited by compounds with the same molecular formula but different alkyl groups attached to either side of a bivalent functional group (e.g., −O− or C=O).
- Methanol (CH₃-OH): Also called wood spirit. Industrially produced by treating carbon monoxide (CO) with hydrogen (H₂) in the presence of catalysts. It is a poisonous substance.
- Ethanol (CH₃-CH₂-OH): Industrially manufactured by the fermentation of molasses using invertase and zymase enzymes.
- 8%−10% ethanol is 'wash'.
- 95.6% ethanol obtained by fractional distillation is rectified spirit.
- 100% ethanol is absolute alcohol.
- Denatured spirit is ethanol mixed with toxic substances (like methanol or pyridine) to prevent its misuse as a beverage.
- Ethanoic Acid (CH₃-COOH): Industrially prepared by treating methanol with carbon monoxide in the presence of a catalyst.
- 5%−8% ethanoic acid, produced by fermentation of ethanol with acetobacter bacteria, is called vinegar.
- Esters: Formed when alcohols react with carboxylic acids. This reaction is called esterification.
- General formula: R−COO−R₁.
- Used to make artificial perfumes and juices because they possess the fragrance of flowers and fruits.
- Orbitals: Regions around the nucleus where there is maximum probability of finding the electrons.
- Quantum Numbers: Used to describe orbitals and electrons.
- Principal Quantum Number (n): Represents shells (principal energy levels, K, L, M, N). Values are 1,2,3,4,….
- Azimuthal Quantum Number (l): Represents subshells (s,p,d,f) and defines the 3D shape of the orbital. Values range from 0 to (n−1).
- Magnetic Quantum Number (m): Represents the difference in orientation of orbitals. For a value l, there are (2l+1) values for m.
- s subshell (l=0): 1 orbital (spherical shape).
- p subshell (l=1): 3 orbitals (dumbbell shape).
- d subshell (l=2): 5 orbitals.
- f subshell (l=3): 7 orbitals.
- The total number of orbitals in each shell is n².
- The maximum number of electrons that can be accommodated in each shell is 2n².
- The maximum number of electrons that can be accommodated in each orbital is 2.
- Maximum electrons per subshell: s-2, p-6, d-10, f-14.
- Energy Order: Determined by the (n+l) values. The subshell with a higher (n+l) value has more energy. If (n+l) values are equal, the subshell with the higher n value has more energy (e.g., 3s > 2p).
- The energy of subshells increases in the order: 1s<2s<2p<3s<3p<4s<3d<… (e.g., 4s fills before 3d).
- Stability Anomaly (Cr and Cu): Configurations with half-filled (d⁵) or completely filled (d¹⁰) d subshells are more stable. To achieve this stability, electrons shift, so d⁴s² becomes d⁵s¹ (Chromium) and d⁹s² becomes d¹⁰s¹ (Copper).
- Block: The block to which an element belongs is the same as the subshell to which the last electron was added.
- Period Number: The period number is the highest shell number in its subshell electron configuration.
- Group Number:
- s-block (Groups 1, 2): Number of electrons in the outermost s subshell.
- p-block (Groups 13–18): 10 + (Total number of electrons in the outermost s and p subshells).
- d-block (Groups 3–12): Sum of the number of electrons in the outermost s subshell and the number of electrons in the d subshell preceding it.
- Down a Group: Ionisation enthalpy decreases. The increasing number of shells increases the distance of the outermost electron from the nucleus, weakening the attractive force.
- Across a Period (L to R): Ionisation enthalpy increases. The nuclear charge gradually increases with no change in the number of shells, leading to a stronger attractive force on the outermost electrons.
- Very high distance between molecules, leading to negligible attractive force.
- Molecules are in constant random motion; collisions with the container walls result in gaseous pressure.
- Collisions are elastic (kinetic energy before and after collision is the same).
- The average kinetic energy of molecules is directly proportional to its temperature.
- The volume of a gas is the volume of the container in which it is occupied.
- Mole: The quantity of a substance containing 6.022 × 10²³ particles (atoms/molecules/ions).
- Avogadro Number (Nₐ): The number 6.022×10²³. Mole is the SI unit of quantity of matter.
- Gram Atomic Mass (GAM): The mass of an element equal to its relative atomic mass in grams. Contains 1 mole of atoms.
- Molar Mass (Gram Molecular Mass): The molecular mass of a compound expressed in grams. Contains 1 mole of molecules.
- Calculating Moles: Number of moles = Given mass / Molar mass.
- Standard Temperature and Pressure (STP): Fixed at 273 K and 1 atm pressure.
- Molar Volume at STP: At STP, one mole of any gas occupies a volume of 22.4 L.
- Number of moles of gases at STP = Given volume (L) / 22.4 L.
- Stoichiometry: In a balanced chemical equation, the coefficients represent the ratios of moles of reactants and products. This allows the determination of required amounts of substances....
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Galvanic Cells
Galvanic cells convert chemical energy into electrical energy.Component Reaction/Property Charge Representation Anode (e.g., Zinc) Where oxidation occurs (Zn → Zn²⁺ + 2e⁻). Negative electrode. Cathode (e.g., Copper) Where reduction occurs (Cu²⁺ + 2e⁻ → Cu). Positive electrode. Electron Flow From anode (Zn) to cathode (Cu) through the external circuit. Salt Bridge Connects the half cells, ensures electrical contact, and maintains electrical neutrality within the internal circuit. -
Electrolytic Cells
Electrolytic cells utilise electrical energy to bring about chemical changes.- Electrolyte: A substance that conducts electricity in molten state or aqueous solution and undergoes chemical changes.
- Electrolysis: The process of chemical change in an electrolyte due to the passage of electricity.
- Anode: Connected to the positive terminal of the battery; oxidation occurs here.
- Cathode: Connected to the negative terminal of the battery; reduction occurs here.
- Example (Aqueous NaCl): Cl₂ gas is liberated at the anode (oxidation), while H₂ gas and OH⁻ ions (forming basic solution) are produced at the cathode (reduction).
- Displacement: A more reactive metal displaces a less reactive metal from its salt solution (e.g., Zn displaces Cu²⁺).
- Agents: The more reactive metal acts as a reducing agent (it is oxidized); the less reactive metal ion acts as an oxidising agent (it is reduced)....
- Hydrogen Displacement: Metals placed above hydrogen in the series can displace hydrogen from dilute acids.
- The object to be coated is the cathode (negative terminal).
- The metal used for plating is the anode (positive terminal).
- The electrolyte is a salt solution of the metal used for plating.
- Primary Cells: Cannot be recharged and reused; become dead when energy is consumed (e.g., dry cells, button cells).
- Secondary Cells: Can be recharged and used again (e.g., lead acid cells, nickel-cadmium cells).
- Lithium Ion Batteries: Secondary cells known for high energy density and long lifespan. They operate via the movement of lithium ions between the anode and cathode.
- Fuel Cells: Galvanic cells that convert the chemical energy from fuel combustion (e.g., hydrogen, methane) directly into electrical energy continuously and with high efficiency.
- Mineral: Naturally occurring metal or compound.
- Ore: Any mineral from which a metal can be extracted easily and economically. Ores typically have high metal content, are abundant, and allow ease of extraction at low cost (e.g., Bauxite (Al₂O₃·2H₂O) for Aluminium).
- Metallurgy: The process of metal extraction, involving three stages: Concentration of ores, Extraction of metal from concentrated ore, and Refining of metal.
- Highly Reactive Metals (K, Na, Mg, Al): Produced by electrolysis.
- Moderately Reactive Metals (Zn, Fe, Sn, Pb):
- Conversion to Oxide:
- Calcination: Heating carbonate or hydroxide ores in limited quantities or absence of air below the melting point (e.g., ZnCO₃ --(heat)--> ZnO + CO₂).
- Roasting: Heating sulphide ores in the presence of air below the melting point (e.g., 2ZnS + 3O₂ --(heat)--> 2ZnO + 2SO₂).
- Reduction: The oxide ore is reduced using a reducing agent (e.g., coke (carbon) or carbon monoxide) (e.g., ZnO + C → Zn + CO).
- Conversion to Oxide:
- Less Reactive Metals (Hg): Separated by controlled heating.
- Charge: Concentrated ore (Fe₂O₃ or Fe₃O₄) mixed with limestone (CaCO₃) and coke (C) is fed into the blast furnace.
- Reduction: Carbon monoxide (CO) is the main reducing agent. Fe₂O₃ + 3CO → 2Fe + 3CO₂.
- Flux and Slag: Limestone decomposes to calcium oxide (CaO), which acts as a basic flux. The flux reacts with acidic impurities (gangue, e.g., SiO₂) to form molten slag (CaSiO₃). The slag floats on the molten iron.
- Products: The molten iron obtained is called pig iron (4% carbon and impurities).
- Steel: Iron containing 0.05% to 1.5% carbon. Alloy steels (e.g., Stainless steel (Fe,Cr,Ni,C), Silicon steel (Fe,Si,C)) are made by adding other metals.
- Concentration of Bauxite: Bauxite (Al₂O₃·2H₂O) is treated by leaching with hot concentrated sodium hydroxide (NaOH) to form sodium aluminate (NaAlO₂). This is then converted and heated to anhydrous alumina (Al₂O₃).
- Electrolysis: Alumina is dissolved in molten
cryolite (Na₃AlF₆). Cryolite reduces the high melting point of alumina
(2017°C) and increases electrical conductivity.
- Cathode (Carbon lining, -): Reduction occurs: Al³⁺ + 3e⁻ → Al (Molten aluminium formed).
- Anode (Carbon rods, +): Oxidation occurs: 2O²⁻ → O₂(g) + 4e⁻.
- The released oxygen oxidises the carbon anodes, necessitating periodic replacement.
- Liquation: Used for low melting point metals (Sn,Pb) by heating them on an inclined surface.
- Distillation: Used for low boiling point metals (Zn,Cd,Hg) where the pure metal vapourises and is condensed.
- Electrolytic Refining: Impure metal is the anode; pure metal is the cathode; and a suitable salt solution of the metal is the electrolyte (e.g., purification of copper)....
- Metals higher in the reactivity series corrode more easily.
- Aluminium, zinc, and tin resist corrosion due to their thin, nonporous oxide coatings. Iron rust (hydrated iron oxide) is porous and powdery, allowing corrosion to continue.
- Cathodic Protection: An important method to prevent corrosion. When two metals are in contact, the more reactive metal acts as the anode and is destroyed (corrodes), thereby protecting the less reactive metal (cathode, e.g., protecting iron by connecting it to magnesium).
- Laboratory Preparation: Ammonium chloride (NH₄Cl) heated with calcium hydroxide (Ca(OH)₂). Ammonia gas has a pungent smell and is basic in nature. It is highly soluble in water.
- Industrial Preparation (Haber Process): Nitrogen and hydrogen combine in a 1:3 ratio at high pressure and temperature. Sponge iron is used as the catalyst. N₂(g) + 3H₂(g) ⇌ 2NH₃(g) + heat The reaction is reversible and exothermic....
- Industrial Preparation (Contact Process):
- Sulphur is converted to sulphur dioxide (SO₂).
- SO₂ combines with O₂ using vanadium pentoxide (V₂O₅) as catalyst to form SO₃.
- SO₃ is dissolved in concentrated H₂SO₄ to produce oleum (H₂S₂O₇). (Direct dissolution of SO₃ in water is avoided because it is highly exothermic and forms a fog/smog).
- Oleum is dissolved in water to produce H₂SO₄.
- Properties: Colourless, denser, and higher viscosity than water.
- Dehydrating Agent: Concentrated H₂SO₄ is a strong dehydrating agent, absorbing hydrogen and oxygen from substances (like sugar) in the same ratio as in water (H:O=2:1).
- Drying Agent: Used to absorb moisture (e.g., in preparation of CO₂, SO₂, HCl). (Cannot be used for NH₃ as they react).
- Oxidising Agent: Concentrated H₂SO₄ reacts with both metals and nonmetals, oxidising them.
- Basicity of an Acid: The number of H⁺ ions that the molecule of the acid can donate. (Monobasic = 1 H⁺, Dibasic = 2 H⁺ (H₂SO₄), Tribasic = 3 H⁺ (H₃PO₄))....
- Alkalies (Arrhenius Theory): Substances that liberate OH⁻ ions and thus increase the concentration of hydroxide ions in aqueous solutions.
- Sodium Hydroxide (Caustic Soda): Industrially produced by the chlor-alkali process. This involves the electrolysis of concentrated aqueous sodium chloride solution (brine) using a membrane cell. Products are H₂ (cathode), Cl₂ (anode), and NaOH.
- Hydrochloric Acid (HCl): Manufactured by the direct combination of hydrogen and chlorine in an exothermic process.
- Natural Nutrients: Carbon, Hydrogen, Oxygen.
- Primary Nutrients (needed in large quantities): Nitrogen, Phosphorus, Kalium (Potassium) (NPK).
- Secondary Nutrients (needed in small quantities): Calcium, Magnesium, Sulphur.
- Essential Qualities of Fertilizers: Must be water-soluble, stable (remain in soil long enough), non-toxic, and should not cause significant pH variations.
- Main Chain Selection: The longest chain containing the maximum number of carbon atoms is the main chain; the remaining atoms or groups are considered branches4.
- Numbering: Carbon atoms must be numbered so that the carbon atom carrying the branch receives the lowest position number5.
- Alkyl Groups: Small branches are called alkyl groups, formed when a hydrogen atom is removed from a saturated hydrocarbon (e.g., Methyl (−CH3), Ethyl (−CH2−CH3))56.
- IUPAC Name Format (Single Branch): Position number of branch + hyphen + name of alkyl group + word root + suffix (ane) (e.g., 2–Methylpentane)67.
- Multiple Branches:
◦ If the same branch appears more than once, prefixes like di (two), tri (three), or tetra (four) are used. Position numbers are separated by commas8. (e.g., 2,5–Dimethylheptane)9.
◦ If numbering from either end gives the same position number for the first branch, numbering should be done to give the second branch a lower position number10.
◦ If a carbon atom has two identical branches, their position numbers must be repeated (e.g., 2,2–Dimethylpropane)11.
Nomenclature of Unsaturated Hydrocarbons
Unsaturated hydrocarbons contain double (alkenes) or triple (alkynes) bonds12. The position of the double or triple bond must receive the lowest position number during chain numbering12. - Alkenes (Double Bond): Word root + hyphen + position of double bond + hyphen + suffix ('ene') (e.g., But–1–ene, Pent–2–ene)13....
- Alkynes (Triple Bond): Word root + hyphen + position of triple bond + hyphen + suffix ('yne') (e.g., But–1–yne, But-2-yne)1617.
Functional Groups
A functional group is an atom or a group of atoms bonded to carbon in an organic compound that determines the distinctive chemical and physical properties of that compound18.
Functional Group - Chain Isomerism: Isomers that have the same molecular formula but differ in the structure of the carbon chain30.
- Position Isomerism: Isomers that have the same molecular formula and the same functional group, but differ in the position of the functional group (this also applies to the position of double or triple bonds)3132.
- Functional Isomerism: Compounds that have the same molecular formula but different functional groups (e.g., Ethanol (CH3CH2OH) and Methoxymethane (CH3−O−CH3)3334.
- Metamerism: Isomerism exhibited by compounds with the same molecular formula but different alkyl groups attached to either side of a bivalent functional group (e.g., −O− or C=O)3536.
- Galvanic Cells
Galvanic cells convert chemical energy into electrical energy117.
Component - Electrolytic Cells
Electrolytic cells utilise electrical energy to bring about chemical changes122.
• Electrolyte: A substance that conducts electricity in molten state or aqueous solution and undergoes chemical changes123.
• Electrolysis: The process of chemical change in an electrolyte due to the passage of electricity123.
• Anode: Connected to the positive terminal of the battery; oxidation occurs here119124.
• Cathode: Connected to the negative terminal of the battery; reduction occurs here119124.
• Example (Aqueous \text{NaCl}): Cl2 gas is liberated at the anode (oxidation), while H2 gas and OH− ions (forming basic solution) are produced at the cathode (reduction)125126.
Reactivity Series
The series in which elements are arranged in the decreasing order of their tendency to get oxidised (reactivity)127.
• Displacement: A more reactive metal displaces a less reactive metal from its salt solution (e.g., Zn displaces Cu2+)128129.
• Agents: The more reactive metal acts as a reducing agent (it is oxidized); the less reactive metal ion acts as an oxidising agent (it is reduced)130....
• Hydrogen Displacement: Metals placed above hydrogen in the series can displace hydrogen from dilute acids122.
Electroplating
Electroplating is the process of coating a layer of one metal onto another metal through electrolysis to enhance beauty and prevent corrosion133.
• The object to be coated is the cathode (negative terminal)133.
• The metal used for plating is the anode (positive terminal)133.
• The electrolyte is a salt solution of the metal used for plating133.
Types of Electrochemical Cells (Energy Sources)
• Primary Cells: Cannot be recharged and reused; become dead when energy is consumed (e.g., dry cells, button cells)134.
• Secondary Cells: Can be recharged and used again (e.g., lead acid cells, nickel-cadmium cells)135.
◦ Lithium Ion Batteries: Secondary cells known for high energy density and long lifespan135. They operate via the movement of lithium ions between the anode and cathode136.
• Fuel Cells: Galvanic cells that convert the chemical energy from fuel combustion (e.g., hydrogen, methane) directly into electrical energy continuously and with high efficiency136. - Concentration of Ores (Removing Gangue)
Method - Highly Reactive Metals (\text{K}, \text{Na}, \text{Mg}, \text{Al}): Produced by electrolysis144145.
- Moderately Reactive Metals (\text{Zn}, \text{Fe}, \text{Sn}, \text{Pb}):
◦ Conversion to Oxide:
▪ Calcination: Heating carbonate or hydroxide ores in limited quantities or absence of air below the melting point (e.g., ZnCO3heatZnO+CO2)146147.
▪ Roasting: Heating sulphide ores in the presence of air below the melting point (e.g., 2ZnS+3O2heat2ZnO+2SO2)147.
◦ Reduction: The oxide ore is reduced using a reducing agent (e.g., coke (carbon) or carbon monoxide) (e.g., ZnO+C→Zn+CO)145148. - Less Reactive Metals (\text{Hg}): Separated by controlled heating144.
Iron Extraction
• Charge: Concentrated ore (Fe2O3 or Fe3O4) mixed with limestone (\text{CaCO}_3) and coke (\text{C}) is fed into the blast furnace149.
• Reduction: Carbon monoxide (CO) is the main reducing agent150. Fe2O3+3CO→2Fe+3CO2150.
• Flux and Slag: Limestone decomposes to calcium oxide (CaO), which acts as a basic flux151. The flux reacts with acidic impurities (gangue, e.g., SiO2) to form molten slag (CaSiO3)150151. The slag floats on the molten iron152.
• Products: The molten iron obtained is called pig iron (4% carbon and impurities)152.
• Steel: Iron containing 0.05% to 1.5% carbon153. Alloy steels (e.g., Stainless steel (Fe,Cr,Ni,C), Silicon steel (Fe,Si,C)) are made by adding other metals154155.
Aluminium Extraction (Hall-Heroult Process) - Concentration of Bauxite: Bauxite (Al2O3⋅2H2O) is treated by leaching with hot concentrated sodium hydroxide (NaOH) to form sodium aluminate (NaAlO2). This is then converted and heated to anhydrous alumina (Al2O3)156157.
- Electrolysis: Alumina is dissolved in molten cryolite
(\text{Na}_3\text{AlF}_6). Cryolite reduces the high melting point of
alumina (2017∘C) and increases electrical conductivity157.
◦ Cathode (Carbon lining, -): Reduction occurs: Al3++3e−→Al (Molten aluminium formed)158.
◦ Anode (Carbon rods, +): Oxidation occurs: 2O2−→O2(g)+4e−158.
◦ The released oxygen oxidises the carbon anodes, necessitating periodic replacement159160. - Refining of Metals
Refining removes impurities to produce pure metal161.
• Liquation: Used for low melting point metals (Sn,Pb) by heating them on an inclined surface161.
• Distillation: Used for low boiling point metals (Zn,Cd,Hg) where the pure metal vapourises and is condensed162.
• Electrolytic Refining: Impure metal is the anode; pure metal is the cathode; and a suitable salt solution of the metal is the electrolyte (e.g., purification of copper)162....
Corrosion and Prevention
Corrosion is a process where a metal reacts with its surrounding medium and undergoes chemical change160.
• Metals higher in the reactivity series corrode more easily165.
• Aluminium, zinc, and tin resist corrosion due to their thin, nonporous oxide coatings. Iron rust (hydrated iron oxide) is porous and powdery, allowing corrosion to continue165.
• Cathodic Protection: An important method to prevent corrosion. When two metals are in contact, the more reactive metal acts as the anode and is destroyed (corrodes), thereby protecting the less reactive metal (cathode, e.g., protecting iron by connecting it to magnesium)166. - Oscillation: A periodic motion where an object moves to and fro at regular intervals of time about its equilibrium position.
- One Oscillation: Completed when the body returns to its initial position in the same direction from where it started (e.g., A → B and returns to A).
- Amplitude (a): The magnitude of maximum displacement to one side from the equilibrium position. SI unit is metre (m).
- Period (T): The time taken for one oscillation. SI unit is second (s).
- Frequency (f): The number of oscillations in one second. SI unit is hertz (Hz).
- Relation between Period and Frequency: Frequency is the reciprocal of the period, f=1/T. As the period increases, frequency decreases.
- Practical Units of Frequency: 1 kilohertz (kHz) = 1000 Hz (10³ Hz); 1 megahertz (MHz) = 1000000 Hz (10⁶ Hz).
- Natural Frequency: The innate frequency at which an object vibrates freely.
- Factors influencing Natural Frequency: Length of the object, size of the object, elasticity, and nature of the material.
- Forced Vibration: The vibration of an object induced by an external vibrating object (e.g., a table vibrating when a tuning fork stem is pressed on it).
- Resonance: Occurs when the natural frequency of the forcing object and that of the forced object are equal. Objects undergoing resonance vibrate with maximum amplitude.
- Applications of Forced Vibration and Resonance: MRI scanning, radio tuning, musical instruments (guitar, violin, stethoscope), megaphones, horns, trumpets, and nagaswarams.
- Wave Motion: The continuous propagation of energy from one part to the other parts through oscillations. It is a mode of transfer of energy.
- Mechanical Waves: Waves that require a medium for transmission (e.g., sound waves, seismic waves).
- Electromagnetic Waves: Waves that do not require a medium for transmission (e.g., radio waves, visible light, X-rays).
- Longitudinal Waves: Waves in which the particles in the medium vibrate parallel to the direction of wave propagation. Sound is a longitudinal wave.
- Compressions (C): Regions of high pressure where air molecules decrease in distance.
- Rarefactions (R): Regions of low pressure.
- Transverse Waves: Waves in which the particles of a
medium vibrate perpendicular to the direction of wave propagation.
Electromagnetic waves are transverse waves.
- Crests: Elevated portions from the equilibrium position.
- Troughs: Lowest portions from the equilibrium position.
- Cycle: One complete oscillation of a particle in wave motion.
- Wavelength (λ): The distance between two consecutive particles which are in the same phase of vibration.
- For transverse waves: Distance between two consecutive crests or troughs.
- For longitudinal waves: Distance between two consecutive compressions or rarefactions.
- Unit: metre (m).
- Speed of Wave (v): The distance travelled by the wave in one second. Unit is m/s.
- Speed-Frequency-Wavelength Relation: The speed of a wave is the product of its wavelength and frequency: v=fλ. When speed is constant, frequency is inversely proportional to the wavelength (f∝1/λ).
- Reflection of Sound: Sound waves reflect after striking objects. Smooth surfaces reflect sound more effectively than rough surfaces.
- Applications of Reflection: Soundboards and curved ceilings in halls are used to reflect sound and spread it.
- Multiple Reflection of Sound: Reflected sound waves get reflected again.
- Echo: The sound heard after a while due to the reflection of the initial sound.
- Persistence of Hearing: The auditory experience produced by a sound persists for about 1/10 of a second.
- Minimum Distance for Echo: For an echo to be heard distinctly (in air, 350 m/s), the reflecting surface must be at least 17.5 m away.
- Reverberation: The lingering of sound, even after the original sound has ceased, due to the multiple reflection of sound.
- Limits of Audibility (Human): For a person with normal hearing, the range is about 20 Hz to 20,000 Hz (20 kHz).
- Infrasonic: Sound with a frequency below 20 Hz.
- Ultrasonic: Sound with a frequency more than 20,000 Hz.
- Uses of Ultrasonic Waves:
- Medical diagnosis and treatment (crushing kidney stones, physiotherapy).
- Ultra sonography (taking images of internal organs).
- Cleaning spiral tubes, machine parts, electronic components.
- In the device called SONAR (Sound Navigation and Ranging) to find the distance to underwater objects.
- Seismic Waves: Waves that travel through the Earth's crust as a result of earthquakes, volcanic eruptions, or massive explosions.
- Tsunami: A series of gigantic ocean waves caused by the displacement of large volumes of water in the sea.
- Lens: A transparent medium where each refracting surface is part of the spheres. A lens has two refracting surfaces.
- Convex Lens (Converging Lens): Thicker in the middle and thinner at the edges. It converges light rays.
- Concave Lens (Diverging Lens): Thinner in the middle and thicker at the edges. It diverges light rays.
- Optic Centre (O): The midpoint of a lens.
- Centres of Curvature (C₁, C₂): The centres of the spheres of which the refracting surfaces are parts.
- Optic Axis: The imaginary line passing through the centres of curvature and the optic centre.
- Aperture: The area of the lens through which light passes.
- Principal Focus (F) - Convex: The point on the optic axis where light rays near and parallel to the optic axis converge after refraction. Considered real.
- Principal Focus (F) - Concave: The point on the optic axis from which light rays near and parallel to the optic axis appear to diverge after refraction. Considered virtual.
- Focal Length (f): The distance from the optic centre of the lens to the principal focus.
- Real Image: Images that can be projected on a screen.
- Virtual Image: Images that cannot be captured on a screen but can only be seen.
- Image Formation by Convex Lens:
- If the object is placed between F and the lens, the image is formed on the same side, and is Erect, Virtual, and Magnified.
- If the object is beyond F, the images formed are Real and Inverted.
- Image Formation by Concave Lens: The image formed is always virtual, diminished, and erect, located between F and the lens on the same side of the object.
- Cartesian Sign Convention:
- All distances should be measured from the optic centre (O).
- Distances in the same direction as the incident ray are positive; opposite direction is negative.
- Distances measured above the optic axis are positive; below are negative.
- Lens Equation: 1/f = 1/v - 1/u (where u is object distance, v is image distance, and f is focal length).
- Magnification (m): The ratio of the height of the
image (hᵢ) to the height of the object (hₒ), or the ratio of the
distance to the image (v) to the distance to the object (u).
- m = hᵢ/hₒ = v/u
- Positive magnification means the image is erect (Virtual); negative magnification means the image is inverted (Real).
- Power of Lens (P): The ability of a lens to converge or diverge light rays. It is the reciprocal of the focal length (P=1/f).
- SI unit: Dioptre (D).
- The power of a convex lens is positive; the power of a concave lens is negative.
- Compound Microscope: Magnifies micro objects.
- Objective: Lens placed close to the object; has a shorter focal length.
- Eyepiece: Lens through which the image is observed; has a greater focal length.
- Objective forms a large, real, inverted image which acts as the object for the eyepiece, which then forms a large and virtual image.
- Refracting Telescope: Used to see distant objects clearly.
- Objective Lens: Has a longer focal length and greater aperture.
- Eyepiece Lens: Has a shorter focal length and lesser aperture.
- The objective forms a small, real, and inverted image of the distant object; the eyepiece views this image virtually.
- Refraction in Prism: When a light ray enters and leaves a prism, it deviates towards the base of the prism due to refraction.
- Dispersion of Light: The phenomenon of splitting up of a composite light (like white light/sunlight) into its component colours (VIBGYOR - Violet, Indigo, Blue, Green, Yellow, Orange, Red). The orderly arrangement of these colours is called the spectrum.
- Deviation and Wavelength: The extent of deviation depends on the wavelength of light (λ).
- Red light (longest λ) deviates the least.
- Violet light (shortest λ) deviates the most.
- Rainbow Formation: A natural phenomenon resulting from the combined effect of refraction, dispersion, and internal reflection of sunlight through water droplets. A rainbow is always formed in a direction opposite to the sun.
- Electromagnetic Spectrum: The orderly distribution of electromagnetic radiations (Gamma rays, X-rays, UV, Visible light, IR, Microwaves, Radio waves). They travel through vacuum at 3×10⁸ m/s.
- Primary Colours of Light: Red, Green, and Blue (RGB). All coloured lights can be created using them.
- Secondary Colours of Light: Formed by combining any two primary colours of light. (e.g., Red + Green = Yellow).
- White Light: Produced by combining red, green, and blue colours of the same intensity.
- Complementary Colours: Pairs of colours (a secondary colour and the primary colour not present in it) that combine to form white light (e.g., Yellow + Blue).
- Primary Dyes: Cyan, Magenta, and Yellow (CMY). Combination of Cyan + Yellow + Magenta yields Dark.
- Persistence of Vision: The visual experience of an object persists for about 1/16 of a second after the object is removed.
- Colour of Transparent Objects (Filters): A filter of a specific colour transmits light of its own colour and its component colours from white light, blocking the others.
- Colour of Opaque Objects: An object appears in the colour of the light that is reflected from it to our eyes.
- A surface reflecting all colours appears white in white light.
- A surface absorbing all colours appears dark.
- Scattering of Light: Irregular and partial directional deviation of light when it encounters microscopic particles in a medium.
- Blue Sky: Light with shorter wavelengths (violet, indigo, blue) undergoes maximum scattering in the atmosphere, spreading the blue light across the sky.
- Red Sun (Sunrise/Sunset): Sun's rays travel a longer distance through the atmosphere. Since red light undergoes the least scattering, it remains prominent in the light reaching the Earth.
- Tyndall Effect: When light passes through a colloidal liquid or suspension, the path of light becomes visible due to scattering by tiny particles.
- Power of Accommodation: The ability of the eye to
change the curvature (and thus focal length) of the lens to adjust so
that the image of the object always falls clearly on the retina.
- Ciliary muscles control lens curvature and focal length.
- Near Point: The nearest point at which an object can be seen clearly (25 cm for healthy eyes).
- Far Point: The farthest point at which an object can be seen clearly (considered infinity).
- Short Sightedness (Myopia): Inability to see distant objects clearly (image forms in front of the retina). Associated with a larger eyeball and more powerful lens. Rectified using a concave lens.
- Long Sightedness (Hypermetropia): Inability to see nearby objects clearly (near point > 25 cm). Associated with a smaller eyeball and less powerful lens. Rectified using a convex lens.
- Presbyopia: Reduction in the efficiency of ciliary muscles in older people, leading to less power of accommodation and an increased near point.
- Magnetic Effect of Electricity: A magnetic field is formed around a current carrying conductor, which can exert a force on a magnetic needle, causing it to deflect.
- Direction of Magnetic Field: Depends on the direction of the current. Reversing the direction of the current reverses the direction of the magnetic field.
- Right Hand Thumb Rule (Straight Conductor): Imagine holding a conductor with your right hand so that the thumb points in the direction of the electric current; the curled fingers indicate the direction of the magnetic field.
- Solenoid: An insulated conductor wound in a spiral shape.
- Factors Influencing Solenoid Magnetic Strength: The number of turns of the conductor per unit length and the magnitude of the current. Magnetic strength is significantly increased by placing a soft iron core inside.
- Solenoid Polarity (Right Hand Rule): If the fingers curl around the coils in the direction of the current, the thumb points towards the north pole. Clockwise current at an end indicates a South Pole; anticlockwise current indicates a North Pole.
- Electromagnet: A device that creates a magnetic field using electricity. Magnetism is temporary (only when current is flowing) and its strength and polarity can be varied.
- Motor Principle: A current carrying conductor, which is free to move and is placed in a magnetic field, exhibits a tendency to deflect.
- Direction of Force: The direction of the force experienced by the conductor is influenced by the direction of the electric current and the magnetic field. If the direction of the current or the magnetic field is reversed, the motion is reversed.
- Fleming's Left Hand Rule: Used to determine the direction of the force/motion (thumb) experienced by a conductor carrying current (second finger) placed in a magnetic field (first finger).
- Electric Motor: A device that converts electric energy into mechanical energy based on the motor principle.
- Main Parts: Armature, Field Magnet, Split Rings (Commutator), and Brushes.
- Split Ring Commutator: Mechanism used to change the direction of current flow through the armature after every half rotation, ensuring continuous rotation in the same direction.
- Moving Coil Loudspeaker: Operates based on the motor principle. It converts electric signals (audio signals) into sound waves (mechanical energy). Electric signals passing through the voice coil (placed in a magnetic field) cause the coil and the attached diaphragm to vibrate, reproducing sound.
- Effect of Electric Current: The useful form of energy into which an appliance mainly converts electric energy.
- Heating Effect of Electric Current: The conversion of electric energy mainly into heat energy.
- Joule Heating (Ohmic Heating): The process of producing heat when electricity flows through a conductor.
- Heating Element: The part used to produce heat, typically made of the alloy nichrome.
- Characteristics of Nichrome: High oxidation resistance, ability to provide heat energy for a long time in a red hot state, and high resistivity.
- Resistivity (ρ): The resistance of a conductor with 1 m² area of cross section and 1 m length. Unit is ohm-metre (Ωm).
- Joule's Law: The quantity of heat produced (H) is
directly proportional to the square of the current (I²), the resistance
(R), and the time (t).
- Equation: H = I²Rt. SI unit is joule (J).
- Alternative Heat Equations (derived from Ohm's Law V=IR): H = V²t/R and H = VIt.
- Voltage and Resistance (Constant V): If voltage is constant, decreasing resistance increases the current, hence increasing the quantity of heat produced.
- Electric Power (P): The quantity of work done (or electric energy converted) by an electrical appliance per unit time (rate of work).
- Power Equations: P = W/t = I²R = V²/R = VI.
- Heat from Power: If power is known, H = Pt.
- Power Marking: The marked power (e.g., at 230 V in India) is available only when the appliance operates at the specified voltage.
- Power Units: Power consumed is in watt (W) (e.g., bulb); power supplied is in volt ampere (VA) (e.g., UPS, solar panel).
- Electric Energy Measurement: Measured in kilowatt hour (kWh) units by a watt hour meter.
- Commercial Unit of Electric Energy: Kilowatt hour (kWh) or unit.
- 1 kWh (1 unit): The energy consumed by an appliance with 1000 W (1 kW) power in one hour.
- Joule equivalent: 1 kWh = 3,600,000 J or 3.6×10⁶ J.
- Formula for kWh: (Power in watt × time in hour) / 1000.
- Energy Star Rating: Indicates energy efficiency (5 stars = highest efficiency). Higher rated appliances have lower electricity bills and lower environmental impact.
- TOD Billing (Time Of the Day): An innovative billing system introduced by KSEB where charges vary based on the time zone (peak hours: 6 pm to 10 pm have the highest charge).
- Energy Crisis: The increase in demand for energy and the decrease in availability.
- Solar Cells: Devices that convert solar energy into electric energy. Solar panels are arrangements of many solar cells. Benefits include producing required electricity and reducing environmental pollution.
- Global Warming: Caused by increasing greenhouse gases (e.g., carbon dioxide, methane).
- Carbon Footprint: The quantity of greenhouse gases emitted by individuals or organizations, expressed as equivalent to the measure of carbon dioxide. Reducing domestic energy consumption and using public transport can reduce carbon footprint.
- Electromagnetic Induction: The phenomenon where an emf is induced in a closed circuit whenever the magnetic flux linked with the circuit changes.
- Induced EMF/Current: The electromotive force developed is the induced emf; the current produced is the induced current.
- Factors Increasing Induced EMF/Current: Increasing the strength of the magnet, increasing the number of turns per unit length of the coil, or increasing the speed of relative motion between the magnet and coil.
- Direct Current (DC): Current that flows only in one direction.
- Alternating Current (AC): Current that continuously changes direction at regular intervals of time.
- Generator: A device that converts mechanical energy into electric energy based on the principle of electromagnetic induction.
- AC Generator: Produces alternating current. Uses slip rings and brushes to transfer AC to the external circuit.
- DC Generator: Produces direct current. Uses a split ring commutator and brushes to transfer DC to the external circuit.
- Power Stations: Centres for large scale electricity generation.
- Hydroelectric: Potential energy of water → Mechanical energy → Electric energy.
- Thermal: Chemical energy (fuel) → Heat energy → Mechanical energy → Electric energy.
- Nuclear: Nuclear energy → Heat energy → Mechanical energy → Electric energy.
- Energy Loss in Transmission: Occurs mainly in the form of heat (H = I²Rt) when electricity is transmitted over long distances.
- Minimising Loss: Use suitable metal wires with low resistivity (e.g., copper or aluminum) and increase voltage to decrease current (as P=VI) without changing the power.
- Mutual Induction: When two coils are near each other, and the current in the first coil (primary) changes, the resulting change in magnetic field induces an emf in the second coil (secondary).
- Transformer: A device that works on the principle of mutual induction to change AC voltage without changing power.
- Step-up Transformer: Increases AC voltage (Vₛ > Vₚ). The secondary coil has more turns than the primary coil (Nₛ > Nₚ). Secondary current is lower than primary current.
- Step-down Transformer: Decreases AC voltage (Vₛ < Vₚ). The secondary coil has fewer turns than the primary coil (Nₛ < Nₚ). Secondary current is higher than primary current.
- Transformer Equation (Ideal): The ratio of voltages is equal to the ratio of turns: Vₚ/Vₛ = Nₚ/Nₛ. Also, VₚIₚ = VₛIₛ (Primary Power = Secondary Power).
- Power Distribution: Electricity is generated at 11 kV, stepped up (e.g., to 220 kV) for long-distance transmission, and then stepped down via distribution transformers (finally to 230 V for houses).
- Household Wiring: Lines are distributed from the MCB board as branches. Appliances are connected in parallel.
- Wire Colours: Phase/Live (Red), Neutral (Black), Earth (Green).
- Short Circuit: Occurs when phase and neutral lines contact with negligible resistance, resulting in excessive current flow.
- Overloading: Excessive current flow when a circuit carries more power than its permissible limit (e.g., connecting a high-power appliance to a normal plug).
- Safety Fuse: Protects equipment from dangers of excessive current (overloading, short circuits). Works based on the heating effect of electricity. Fuse wire has a relatively low melting point and is connected in series to the phase line.
- MCB (Miniature Circuit Breaker): Used in branch circuits; operates automatically (trips) due to excessive current. Works using the magnetic effect and heating effect.
- ELCB (Earth Leakage Circuit Breaker): Disconnects the circuit automatically if there is current leakage, preventing electric shock. (RCCB is a safer modern alternative).
- Three Pin Plug and Earthing: Ensures safety for high power appliances by connecting the appliance to the earth wire.
- Simple Machines: Devices that make exertion easier by changing the magnitude of the effect of force or the direction of the force, or both.
- Six Types of Simple Machines: Lever, pulley, wheel and axle, inclined plane, screw, and wedge.
- Effort (E): The force applied to a simple machine.
- Load (L): The force the simple machine has to overcome.
- Mechanical Advantage (MA): The ratio of the load to the effort. MA = Load/Effort. MA has no unit.
- Work Done: There is no gain in work by using simple machines.
- Lever: A rigid rod that can rotate around a fixed point called the fulcrum (F).
- Load Arm (LA): Perpendicular distance from the load (L) to the fulcrum (F).
- Effort Arm (EA): Perpendicular distance from the effort (E) to the fulcrum (F).
- Principle of a Lever (Equilibrium): Load × Load arm = Effort × Effort arm.
- MA of Lever: MA = Effort arm / Load arm.
- Lever Classification:
- First Order Lever: Fulcrum (F) is between the load (L) and the effort (E). MA can be greater than one, equal to one, or less than one. Examples: common balance (MA=1), scissors, seesaw.
- Second Order Lever: Load (L) is between the effort (E) and the fulcrum (F). The effort arm is longer than the load arm. MA is always greater than one.
- Third Order Lever: Effort (E) is between the load (L) and the fulcrum (F). The load arm is longer than the effort arm. MA is always less than one. Advantage: Helps to handle objects safely with ease. Examples: Tongs, fishing pole, forceps.
- Fixed Pulley: Rotates around a stationary axle; similar to a first order lever (Load Arm = Effort Arm). MA is one. Advantage: changes the direction of the applied force.
- Movable Pulley: Moves with the load; similar to a second order lever. The MA of a single movable pulley is 2.
- System of Pulleys (n movable pulleys): MA is 2ⁿ in the first system. In the second system, MA is the total number of rope segments supporting the load.
- Wheel and Axle: Energy is transferred by applying effort to the wheel (Radius R) to rotate the axle (Radius r). MA = R/r (greater than one).
- Gears: Mechanical devices using interlocking toothed wheels to transfer motion or force. Used to change speed (e.g., connecting engine to a large toothed wheel decreases speed but increases efficiency/torque).
- Inclined Plane: Used to lift objects to a height (h) by pushing them along a length (l).
- MA = Length of inclined plane (l) / Height of inclined plane (h). A longer inclined plane provides more MA.
- Wedge: A double inclined plane (e.g., knife, axe, chisel). Easier to use if it is longer and thinner.
- MA = length of the inclined plane of the wedge (l) / thickness of the wedge (h).
- Screw: Can be considered an inclined plane wrapped around a cylinder.
- Pitch (h): The distance between two consecutive threads.
- MA = length of one thread (l) / pitch (h).
Chapter 1: Design Factory
Chapter 2: Let’s Prepare a Newspaper
Chapter 3: Computer Language
Chapter 4: Cyberspace
Chapter 5: Make the Web Look Stylish
Chapter 6: The World of Robots
Chapter 7: Learning Science Through Computers
Chapter 8: Let’s Give Life to Pictures
| Name of the Room | Use |
|---|---|
| Animation | This room is where you animate the position, rotation and size of the current objects. |
| Drawing | This room is used to draw, colour, and edit the drawings.... |
| Browser | Used to browse to the folder where the images are stored and load them. |
| Tool Name (Implied) | Tool Use (Provided in Source) |
|---|---|
| Selection Tool | To adjust the position, rotation, size of the objects. |
| Draw Geometrical Figures Tool | To draw geometrical figures. |
| Type Tool | (Use not explicitly defined in the source table). |
Chapter 9: To the Information Storehouse
Chapter 10: Software and Freedom
Chapter 1: Design Factory
Chapter 2: Let’s Prepare a Newspaper
Chapter 3: Computer Language
Chapter 4: Cyberspace
Chapter 5: Make the Web Look Stylish
• a) Inline18
• b) Internal
• c) External
• d) Outline
(Inline cascading styles involve adding styles directly using the style
attribute within the opening tag of an HTML element2122.)
3. While using external cascading style sheet, which tag can be used to include the stylesheet in an HTML page ?23
• a) rel
• b) type
• c) css
• d) link23
(The external CSS file is linked using the <link rel="stylesheet" type="text/css" href="filename.css"> code in the <head> section24.)
Chapter 6: The World of Robots
Chapter 7: Learning Science Through Computers
Chapter 8: Let’s Give Life to Pictures
Use
Animation
This room is where you animate the position, rotation and size of the current objects4142.
Drawing
This room is used to draw, colour, and edit the drawings41....
Browser
Used to browse to the folder where the images are stored and load them44.
2. Given below are the icons of some important tools in OpenToonz. Complete the table with their uses.4041
Tool Name (Implied)
Tool Use (Provided in Source)
Selection Tool
To adjust the position, rotation, size of the objects4145.
Draw Geometrical Figures Tool
To draw geometrical figures4146.
Type Tool
(Use not explicitly defined in the source table)4146.
Chapter 9: To the Information Storehouse
Chapter 10: Software and Freedom
Chapter 1: Design Factory
This chapter focuses on Graphic Designing, which is the creative work involved in making posters, banners, and boards.
Key Concepts and Tools:
Chapter 2: Let’s Prepare a Newspaper
This chapter focuses on designing pages for publication using Desktop Publishing (DTP) software.
Key Concepts and Tools:
Chapter 3: Computer Language
This chapter introduces how computers are instructed and the basics of Python programming.
Key Concepts of Computer Programming:
Control Flow and Operators:
Python Graphics:
Chapter 4: Cyberspace
This chapter explores the digital environment and online interactions.
The Digital Environment:
Digital Assets and Advanced Technology:
Cyber Ethics and Safety:
Chapter 5: Make the Web Look Stylish
This chapter discusses Cascading Styles used to make webpages attractive and efficient.
Key Concepts of Cascading Styles:
Chapter 6: The World of Robots
This chapter covers the components, functioning, and applications of Robotics.
Robotics Fundamentals:
Chapter 7: Learning Science Through Computers
This chapter covers using software tools like Stellarium and Geographic Information Systems (GIS) for educational purposes.
Stellarium (Desktop Planetarium):
Geographic Information System (GIS):
Geometry of Equations (GeoGebra):
Chapter 8: Let’s Give Life to Pictures
This chapter details the process and techniques of animation, particularly using OpenToonz.
Animation Core Concepts:
OpenToonz Software:
Chapter 9: To the Information Storehouse
This chapter focuses on Database Management Systems (DBMS) and Structured Query Language (SQL).
Database Concepts:
SQL Queries (Retrieving Information):
Chapter 10: Software and Freedom
This chapter discusses the history of software development, licenses, and the Free/Open Source movement.
Software Code and Principles:
Software Licenses and Freedoms:
History of Free Software:
Chapter 1: Design Factory
This chapter focuses on Graphic Designing12, which is the creative work involved in making posters, banners, and boards2.
Key Concepts and Tools:
• Software: Free software available for graphic editing includes GIMP, Krita, Inkscape, Scribus, and LibreOffice Draw3.
• Vector vs. Raster Images:
◦ Raster Images (e.g., JPEG, PNG) are made of pixels and may lose quality (become pixelated) when scaled4.
◦ Vector Images (e.g., SVG, EPS) are created using mathematical
equations defining lines and shapes, can be resized without losing
quality, and generally have small file sizes5.
• Inkscape: A Free vector graphic designing software used for
high-quality designs such as logos, illustrations, posters, brochures,
and typography36. Its default file format is Scalable Vector Graphics
(SVG), and it supports other formats like AI, PDF, and PNG6.
• Poster Design Steps: Start by creating a canvas7, adding text
effectively, and arranging drawings, images, and shapes attractively7.
• Canvas/Page Setup: In Inkscape, use File → Document Properties
(shortcut: Shift + Ctrl + D) to adjust page size, units, and
orientation58.
• Drawing and Editing Tools (Inkscape):
◦ Create Rectangle & Squares (R)9.
◦ Select and Transform Objects (S) changes object size9. Holding Ctrl while resizing keeps dimensions proportional9.
◦ Colours can be applied using Fill Color (fill) or by holding Shift while selecting a colour (stroke/border)9.
◦ The Bezier Curve tool (B) is used to create regular lines and curved
shapes10. It helps draw complex shapes, logos, and fonts11.
◦ Edit path by nodes (N) is used to curve or adjust lines12.
◦ Path → Intersection is used to retain only the overlapping common part of two selected shapes13.
◦ Align and Distribute (Shift + Ctrl + A) is used for arranging design elements with accuracy14.
◦ Grouping objects is done using Ctrl+G15.
◦ Opacity controls colour transparency (0% transparency means the object cannot be seen)1116.
◦ The Gradient tool and Blur effect can be used to create shading and three-dimensional effects17.
• Exporting: Inkscape files can be exported to PNG, JPG, and WEBP
formats18. For screen display, 96dpi is sufficient, while for print,
300dpi is preferred18.
Chapter 2: Let’s Prepare a Newspaper
This chapter focuses on designing pages for publication using Desktop Publishing (DTP) software19.
Key Concepts and Tools:
• Desktop Publishing (DTP): A method of preparing and printing pages
using designing software on a computer20. It allows a single person or
team to quickly complete stages previously handled by multiple
professionals (typists, graphic designers, typesetters)20.
• DTP Software: Scribus is a popular open-source DTP software used for
designing magazines, books, and newspaper pages21. Other DTP software
includes LaTeX, Adobe InDesign, Microsoft Publisher, and QuarkXPress21.
• Page Design Elements: In newspapers, content is often divided into
columns2223. Design relies on images, fonts, headings, colours,
arrangement of letters, and blank spaces22.
• Scribus Features:
◦ Documents are started by selecting settings like Page Layout, size, orientation, and margin from the New Document window24.
◦ The Shape tool is used to draw shapes, and dimensions can be entered in the Properties window2526.
◦ Node Editing allows changing the shape of figures by adjusting nodes2728.
◦ Drop Shadow adds shadow to objects29.
◦ Text frames (T) are necessary to include and format text3031.
Formatting options are available in the Text Properties window3233.
◦ The Line tool can be used to add lines; holding the Ctrl key ensures the line is straight3435.
◦ The Image Frame tool is used to include images36. After inserting an
image, it can be adjusted to the frame using Image → Adjust Image to
Frame37.
◦ QR Codes can be generated using the Barcode icon, selecting Two dimensional symbols and QR Code3839.
◦ Text can be arranged into columns using the Columns & Text Distance tab in the Text Properties window40.
◦ The Text Overflow Icon appears at the bottom right of a text frame if the content exceeds the frame's capacity41.
◦ To arrange images among text, adjustments must be made in the Contour
Line of the image using Shape → Text flow around frame4243.
◦ Background colour can be set by drawing a large rectangle shape and
using Level → Lower to bottom to place it behind the text44.
◦ Documents are exported to PDF format using File → Export for printing4445.
• Career Opportunities: DTP professionals work as graphic designers,
layout artists, desktop publishers, and print production specialists in
various industries46.
Chapter 3: Computer Language
This chapter introduces how computers are instructed and the basics of Python programming4748.
Key Concepts of Computer Programming:
• Binary Language: Computers are electronic devices and only understand
ON and OFF states, represented by the symbols 1 and 0 (binary
language)4950. These states are also known as High/Low or True/False50.
• High-level Languages: Languages like Python, C, and Java that humans use to give instructions48....
• Translator Programs: Convert high-level language instructions into binary language50.
◦ Compilers: Convert instructions completely into a separate binary file (executable file) before execution (e.g., C, C++)5253.
◦ Interpreters: Process and execute code line by line during execution,
requiring the source code to be present (e.g., Python)5253.
• Programming: The process of giving the necessary instructions to computers to perform a specific task53.
• Algorithm: The steps for solving a problem written in a specific order54.
• Python: An open-source programming language developed by Guido van Rossum in 1990, known for its simple syntax4855.
• Programming Basics (Python):
◦ Programs are typically saved with the .py extension56.
◦ Run using the command python3 filename.py in the terminal57.
◦ Variables temporarily store data58.
◦ Datatype indicates the type of data (integers, strings, etc.)58.
◦ The input() function collects data, which is provided in text format (string)59.
◦ The int() function is used to convert data from string form to integer form so mathematical operations can be performed6061.
◦ IDLE (Integrated Development Environment) is specialized software used for easily running and fixing errors in programs62.
Control Flow and Operators:
• Conditional Statements (Branching): Control the flow of the program based on whether a condition is met63.
◦ The if...else statement checks a condition6465.
◦ The if...elif...else format checks multiple conditions sequentially66.
◦ Syntax refers to the terminologies and rules for writing programs67.
• Loop Statements (Iteration): Used to repeat instructions68.
◦ while loop: Repeats statements as long as a condition is true6869.
◦ for loop: Often used with the range statement to arrange a set of
numbers systematically (e.g., range(1, 101) gives numbers 1 through
100)7071.
• Operators: Arithmetic (+, -, *, /, %), Assignment (=), Comparison (==,
>, <, >=, <=, !=), and Logical (and, or, not) are used in
Python72....
Python Graphics:
• The turtle graphics module can generate graphical output75.
• The command from turtle import * adds all functions from the module76.
• forward is used to draw a line77.
• right(90) or left(90) rotates the drawing 90 degrees78.
• Lists store different data in a single string (e.g., colours) and can be easily iterated through using a for loop7980.
Chapter 4: Cyberspace
This chapter explores the digital environment and online interactions8182.
The Digital Environment:
• Cyberspace: The virtual space where digital devices (computers,
servers, phones, networks) and the information transferred between them
are all linked82.
• Internet: A global network of interconnected computers and physical
infrastructure (servers, cables, routers)83. It is a component of the
broader concept of cyberspace83.
• Cyberworld: Specific virtual spaces within cyberspace, such as virtual reality platforms or online multiplayer games84.
• Digital Footprint: The trace of information created while using the Internet (websites visited, posts shared, apps used)85.
• Cyber Identity: A person’s digital representation shaped by online information and activities86.
• Cyber Infrastructure: Includes the Internet, hardware, network
protocols, information, databases, web pages, and security systems87.
• Internet of Things (IoT): A network of physical objects connected to
the Internet, equipped with sensors and software to collect data and
interact88.
Digital Assets and Advanced Technology:
• Metaverse: An immersive platform/vast virtual world that integrates
Augmented Reality (AR), Virtual Reality (VR), Artificial Intelligence
(AI), and Blockchain to create an artificial world89. Users are
represented by Avatars8990.
• Digital Assets: Financial assets that exist only in digital form and
hold value (e.g., digital currencies, digital wallets, domain names,
software, points from online shopping)91.
◦ NFT (Non-Fungible Token): Valuable, proprietary digital items such as digital art, music, or rare in-game items91.
◦ Cryptocurrency: A decentralized digital currency secured by cryptography and Blockchain technology (e.g., Bitcoin)92.
• Big Data: Very large and complex datasets generated rapidly in
cyberspace (e.g., from social media, e-commerce, and IoT devices) that
traditional data processing software cannot handle efficiently93.
◦ Explicit data collection is when a user knowingly provides information (e.g., filling forms)94.
◦ Implicit data collection gathers information without the user explicitly providing it (e.g., browsing history, location)94.
Cyber Ethics and Safety:
• Plagiarism: The act of presenting someone else's ideas, expressions, or work as your own95.
• References: Details of the original sources of information used, required to acknowledge intellectual contributions95.
• Reliable Sources: When searching for information, rely on sources that
are authentic, reliable, and up to date9697. Examples include reports
from scientific conferences, journals, books, and recognized agencies98.
Websites like www.scholar.google.com and www.semanticscholar.org help find credible scientific publications99.
• Dangers of Excessive Use: Can lead to issues like FOMO (Fear of
Missing Out), Gaming Disorder, Cyberchondria, Nomophobia (No Mobile
Phobia), and Tech Neck100101. Solutions include limiting screen time and
Digital Detox102.
• Netiquette (Cyber Etiquette): Rules for good behaviour online,
emphasizing kindness, respect, avoiding harmful messages, and not
sharing other people's personal information103104.
Chapter 5: Make the Web Look Stylish
This chapter discusses Cascading Styles used to make webpages attractive and efficient105106.
Key Concepts of Cascading Styles:
• Structure: Style instructions consist of a property and its
corresponding value, separated by a colon (:), and completed with a
semicolon (;)107108.
• Style Properties: color sets text colour; background-color sets
background colour; text-align: center; centres text; and font-weight:
adjusts font thickness108109.
• Measurements: CSS uses absolute measurements like pixels (px),
centimetres (cm), and inches (in), and relative dimensions like em and
%110.
• Types of Cascading Styles:
1. Inline Cascading Style: Style is added directly using the style
attribute within the opening tag of an HTML element106111. This leads to
code repetition and complex maintenance112113.
2. Internal Cascading Style: Styles are defined once within the <style> tag in the <head> section of the same HTML file114115. This is more convenient than inline style as the tag needs to be styled only once115116.
3. External Cascading Style Sheets (CSS): This method defines styles in a
separate file (saved with the .css extension) and applies them to all
required web pages117118. This avoids repetition across multiple pages
(like Wikipedia)117.
▪ The CSS file is linked to the HTML page inside the <head> tag using the code: <link rel="stylesheet" type="text/css" href="filename.css">119120.
• Cascading Style Order (Priority): If an element has multiple
conflicting styles, the browser follows this priority order (highest to
lowest): Inline Style > Internal Style > External Style121122.
• HTML Tags: The <div> tag (Division tag) is useful for dividing the code in a webpage into different sections123.
Chapter 6: The World of Robots
This chapter covers the components, functioning, and applications of Robotics124125.
Robotics Fundamentals:
• Robotics: The science that studies the design, construction,
operation, and control of robots, integrating electronics, mechanical
engineering, and computer science126.
• Robot Functioning: Robots perceive their surroundings using sensors,
analyze the information, make decisions based on instructions, and
act127.
• Basic Components:
◦ Input Devices (Sensors): Gather information (e.g., Light Sensor, IR Sensor, Microphone, Camera)127128.
◦ Control Unit: Microcontrollers or Microprocessors process data and manage output (e.g., Arduino, Raspberry Pi, ESP32)126127.
◦ Output Devices: Display results or perform actions (e.g., LEDs, Buzzers, Motors)126127.
◦ Actuators: Components enabling automatic movement (e.g., servo motors, stepper motors)127.
• Arduino: An open-source hardware/software platform129. The Arduino UNO
board features the ATmega328P microcontroller chip130131. It includes
DIGITAL I/O PINs (0-13) (some support PWM for controlling devices like
servo motors) and Analog Input pins131132.
• Circuit Building: A breadboard allows building and reusing circuits without soldering133.
• LED Circuits: An LED (Light Emitting Diode) must be connected with a
resistor in series to prevent damage134135. To control the LED (e.g.,
blinking), it must be connected to a Digital Pin on the Arduino136.
• PictoBlox Programming Modes:
◦ Upload Mode: The program is fully uploaded to the Arduino's memory, allowing it to run independently without the computer137.
◦ Stage Mode: The Arduino runs based on continuous instructions received
via the USB cable, requiring the computer connection138.
• Signals: Instructions are given using HIGH (ON/1) and LOW (OFF/0) signals139.
• Servo Motor: A motor designed to rotate only through specific angles (e.g., 0 to 180 degrees)140. Controlled using PWM140.
• IR Sensor Module: Detects obstacles using infrared waves141.
• AI and Robotics: Artificial Intelligence (AI) enables machines to
imitate human intelligence142. Combined with robotics, AI allows for
precision tasks like manufacturing, surgery, and face recognition143144.
The Face Detection extension in PictoBlox (used in Stage Mode) can be
used for systems that recognize human faces145146.
Chapter 7: Learning Science Through Computers
This chapter covers using software tools like Stellarium and Geographic Information Systems (GIS) for educational purposes147.
Stellarium (Desktop Planetarium):
• Stellarium: A free desktop planetarium software that simulates sky views and celestial phenomena148.
• Setup: To observe a celestial body, one must set the Place of
observation, observation time (date and time), and select the celestial
body149.
• Midnight Sun: To view the midnight sun, the observation location must
be set to a city north of the Arctic Circle, such as Tromso,
Norway150.... The phenomenon, also known as White Nights, occurs during
summer when the sun is visible all day without setting148....
• Solstice: The Summer Solstice (June 21) is when the Sun is overhead at the Tropic of Cancer155.
• Tools: The Location Window (F6) sets the place150. The Date/Time
Window (F5) sets the time156. The Search Window (F3) finds celestial
bodies157. Time speed can be adjusted using Increase Time Speed (L)154.
Geographic Information System (GIS):
• Disaster Risk Area Map: A map highlighting vulnerabilities and
potential hazards, essential for planning disaster prevention and rescue
operations158159.
• GIS Software: Records features and spatial information of the Earth's surface in layers160. Used to prepare resource maps161.
• Examples of GIS Software: Quantum GIS (QGIS) and GRASS are free
software; Arc GIS is proprietary software160162. School GIS is an online
portal for school information162163.
• QGIS Operations: Data (e.g., CSV files containing landslide details)
can be added as a new layer using Layer → Add Layer → Add Delimited Text
Layer164165. The Identify Features tool is used to view information
about a specific point on the map166.
• Digital Elevation Model (DEM): A 3D graphical representation of
elevation data, typically stored as a raster image file (e.g.,
.tif)167168.
• Slope Analysis: DEM data is used to calculate the slope of an area
using QGIS Processing Toolbox → GDAL → Raster analysis → Slope169.
Different colours are assigned based on slope degree using the Symbology
properties (Render type: Singleband pseudocolor)170.
• Printing: Maps are printed using the New Print Layout feature171172.
Geometry of Equations (GeoGebra):
• GeoGebra: Interactive geometry software173.
• Input Method: Geometric structures like points and lines can be
created by typing commands in the Input Bar174. For example, A(1,2)
creates point A174. Segment(A,D) draws a line segment175.
• Drawing Equations: Typing equations like x=1 creates a line parallel
to the Y-axis176177. Typing y=x^2 creates a parabolic shape178179.
Typing x^2+y^2=2 creates a circle179.
• View: The index numbers of marked points appear in the Algebraic View180.
Chapter 8: Let’s Give Life to Pictures
This chapter details the process and techniques of animation, particularly using OpenToonz181.
Animation Core Concepts:
• Persistence of Vision: The unique feature of the human eye where an
image remains on the retina for a short time (one sixteenth of a
second), causing sequential images viewed rapidly to be perceived as
continuous motion182183.
• Phenakistiscope: The first device used to simulate animation (early 19th century)184.
• Flipbook: A type of illustrated book using a series of gradually
changing images to create the feeling of movement when pages are turned
continuously185.
• Animation Preparation: Requires a theme, story, scenes, and a
storyboard (detailed preparation of each scene)186187. Character Design
focuses on shape variation, colour selection, and modifiability188189.
• Animation Types: 2D animation (based on 2D images, e.g., The Jungle
Book) and 3D animation (based on 3D shapes, e.g., Shrek)190.
• Frame Rate (FPS): The number of still images (frames) displayed per
second, which determines the naturalness of the movement191. A 5-second
animation at 12 FPS requires 60 frames192.
OpenToonz Software:
• OpenToonz: Free animation software used for drawing, animation, and sound193.
• Workspaces (Rooms): Animation (animating position/rotation/size), Drawing (drawing/colouring/editing), and Browser194195.
• Xsheets: Organize animation content in columns (tracks) and frames (cells), similar to timelines196.
• Vector Level: Used to draw vector images within a column197198.
• Tweening: A technique where the software automatically creates the
changes (position, size, etc.) of an object between designated Key
Frames199200. Position Tweening is used for movement201.
• Image Sequences: Pre-prepared sequences of images can be added to frames to enable subtle movements202.
• Saving and Exporting: Project files are saved with the .tnz
extension203. Animation is exported as a video file (e.g., MP4) using
Render → Fast Render to MP4202204.
• Combining Scenes: Prepared scenes can be combined using video editing software like Kdenlive205.
Chapter 9: To the Information Storehouse
This chapter focuses on Database Management Systems (DBMS) and Structured Query Language (SQL)206207.
Database Concepts:
• Database: A systematic collection of tables containing interrelated information208.
• DBMS: Software used to store, find, analyze, change, and eliminate information from interconnected tables206.
• Table Components:
◦ Fields: Columns in a table (e.g., Player_Name, Total_Runs)209.
◦ Datatypes: The type of data collected in a field (e.g., Text, Number/Integer, Date, Image, Audio, Video)209210.
◦ Records: Rows in a table containing all the information collected about a single entry210211.
• Keys:
◦ Primary Key (PK): A field used to uniquely identify each record in a table (e.g., Player_ID, Admission Number)211212.
◦ Foreign Key: A field in one table used to establish a relationship by referring to the primary key of another table213.
• DBMS Software: Important DBMS software includes Oracle, MySQL, SQL
Server, and sqlite208. SQLite is a free software DBMS where the database
is stored as a single file214.
SQL Queries (Retrieving Information):
• Structured Query Language (SQL): A specialized computer language used
by DBMSs to communicate, select information, create/modify tables, and
insert/edit/delete information207215.
• Retrieving Data: Queries are run in the Execute SQL tab207.
◦ Example: select Total_Runs from Player where Player_Name='Sachin
Tendulkar' retrieves the total runs scored by Sachin Tendulkar207.
◦ select * from Player retrieves all details from the Player table216.
◦ Queries can join data from multiple tables by relating Foreign Keys to Primary Keys213217.
Chapter 10: Software and Freedom
This chapter discusses the history of software development, licenses, and the Free/Open Source movement218.
Software Code and Principles:
• Source Code: Human-readable instructions written in a programming
language; can be edited219. Python programs are typically distributed as
source code220.
• Object Code (Executable Code): The converted machine-readable format; cannot be easily modified219.
• Benefits of Open Source Code: Allows users to trust the program, learn
from it, improve it, reduce bugs, lower costs, and disseminate
knowledge221222.
• Software Publishing Platforms: GitLab, GNU Savannah, Gitea, GitHub,
SourceForge are online services that help publish and manage
software223224.
Software Licenses and Freedoms:
• Software License: Defines the rights granted to users regarding how the software may be used225.
• GNU Public Licence (GPL): A license that ensures user freedom to use
the software for any purpose, read/learn the source code, copy/edit it,
and redistribute modified/unmodified versions225.... GIMP is distributed
under GPL225.
• Free Software: Prioritizes user freedom and knowledge dissemination ("free as in liberty," not necessarily zero cost)228229.
• Open-Source Software: Emphasizes universal accessibility,
collaboration, and innovation229. Examples include Apache License (used
for Android OS) and BSD License229230.
• FLOSS: Free/Libre and Open Source Software (a middle-ground
approach)229. Mozilla Firefox uses the Mozilla Public License (a FLOSS
license)231.
• Proprietary Software (EULA): Software that typically provides only
object code and has usage restrictions, sometimes requiring a new
license for each system (e.g., Microsoft Windows, Apple iOS)226228.
• Copyleft: A licensing method that uses copyright law to legally
guarantee users the freedom to use, copy, modify, and redistribute a
program232233.
History of Free Software:
• Richard Stallman: Founded the GNU Project in 1983 to create and make
freely available software234235. He established the Free Software
Foundation (FSF) in 1985 to support these efforts235.
• GNU/Linux: The GNU Project aimed to rewrite the Unix operating system
without using its code, hence the name GNU (GNU is not Unix)233. The GNU
components were combined with the Linux kernel (created by Linus
Torvalds) to form the GNU/Linux operating system236. The kernel
interacts directly with hardware; the shell (e.g., GNU Bash) interacts
with the user237238.
• Development Models: Proprietary software follows the Cathedral Model;
FOSS follows the Bazaar Model, relying on collaborative contribution239.
• Version Control: Git (created by Linus Torvalds) is an online software
used to store, manage, and track versions of software
collaboratively240.
• Open Hardware: A growing movement releasing hardware components under
free manufacturing licenses (e.g., Arduino microcontrollers)241242.write
without page reference numbers
Chapter 1: Genetics of Life
Question 1: Are basic building blocks of DNA and RNA the same? Explain.
Answer: The basic building blocks, called nucleotides, are not entirely the same.
Question 2: Analyse the statements and choose the appropriate one.
i. F1 has similarity with both the parents.
ii. F1 has no similarity with any of the parents’ character intermediate to them.
iii. F1 has similarity with one of the parents
Answer: c) i - Co-dominance, ii - Incomplete dominance, iii - Dominance.
Question 3: Which of the following is contributed by organisms that reproduce sexually, to their offspring?
a) All genes
b) Half of their genes
c) One fourth of their genes
d) Double the number of genes
Answer: b) Half of their genes.
Question 4 (Abridged): A tall pea plant with purple flowers (dominant character) is crossed with a dwarf plant with white flowers.
b) Did characters that differ from the parents appear in the F2 generation? Why?
Answer: Yes, characters that differed from the parental
plants (e.g., tall with white flowers, dwarf with purple flowers)
appeared in the F2 generation. This occurs because when two or more
different traits are combined, each trait is inherited independently to
the next generation without mixing.
Question 5: How does dominance, co-dominance and incomplete dominance differ from one another?
Answer: These inheritance patterns differ based on how the traits are expressed in the hybrid (F1) generation:
Question 7: Even though a gene responsible for
certain characters has more than two alleles, why does that particular
gene have only two alleles in an individual?
Answer: While a gene may exhibit Multiple Allelism
(meaning the gene pool of the human population, for example, has more
than two alleles, such as Iᴬ, Iᴮ, and i for blood group determination),
an individual organism inherits only two alleles for that character, one
from each parent.
Question 8: Although the DNA possesses all genetic information for protein synthesis, RNA is also required for protein synthesis. Why?
Answer: RNA is crucial because the process of protein synthesis involves multiple steps requiring different types of RNA:
Question 9: How do co-dominance and multiple
allelism function in the determination of blood group in the ABO blood
grouping in human beings? Explain.
Answer:
Question 10: All ova formed in females contain one type of sex determining chromosome. Why?
Answer: The normal genetic constitution for a female is
44 + XX. When gametes (ova) are formed through meiosis, the pair of
factors (sex chromosomes) separate. Since both sex chromosomes are
identical (X and X), every ovum produced will contain only one type of
sex chromosome: the X chromosome.
Chapter 2: Paths of Evolution
Question 2: Although dolphins have a larger brain than that of humans, the level of thinking, language skills and social relationships are higher in humans. Evaluate this statement based on the following indicators:
Question 3: Redraw the figure of the neuron and label the following parts by writing their names.
(a) The part of the neuron that receives impulses from the adjacent neuron
(b) Part that contains neurotransmitter
(c) Part that acts as insulator
Answer:
(a) The part of the neuron that receives impulses from the adjacent neuron is the Dendrites (branches of the Dendrons).
(b) The part that contains neurotransmitter is the Synaptic knob (seen at the tip of the axonite).
(c) The part that acts as an insulator is the Myelin sheath (which is made up of a shiny white fat and increases the speed of transmission of messages).
Question 4:
Darwin failed to explain the reasons of variation even though he argued
that variations occur continuously in organisms. Evaluate this
statement based on the findings of Neo Darwinism.
Answer: The statement is valid as Charles Darwin did
not have knowledge regarding the genetic basis of variations and
inheritance. Neo Darwinism addressed this limitation by incorporating
later discoveries, such as those made by Gregor Mendel, about
chromosomes and genes. Neo Darwinism recognizes that the causes of
variations that lead to evolution are genetic changes (mutations), genetic recombination during sexual reproduction, and gene flow.
Question 5:
Observe the illustration and answer the questions. (Illustration shows
Central Nervous System (A) connected to body parts via nerves (B)).
(a) Identify the nerves A and B.
Answer: A: Central Nervous System (Includes Brain and Spinal Cord). B: Peripheral Nervous System (Includes cranial nerves, spinal nerves, receptors, and nerve ganglia that connect the central nervous system to the organs).
(b) Are messages being exchanged between A and B? Explain.
Answer: Yes, messages are continuously exchanged
between the Central Nervous System (A) and the Peripheral Nervous System
(B). The spinal cord (part of A) transmits messages from different
parts of the body (via B) to the brain, and transmits instructions from
the brain (via A) to different parts of the body (via B).
Question 6: A table that includes the parts of spinal cord and their functions is given below. Arrange column B appropriately in accordance with column A of the table.
| A. Part | B. Functions/ Peculiarities |
|---|---|
| Central canal | Fluid present here nourishes the spinal cord |
| White matter | Neurons with myelin sheath are numerous |
| Dorsal root | Transmits impulses to the spinal cord (messages from the body) |
| Grey matter | Cell body of neurons are numerous (also parts of neurons without myelin sheath) |
Question 7:
Based on the information obtained from fossils, some human ancestors
and their characteristics are given below. Find out the one which is
arranged correctly from the given answers.
(A) Homo habilis (i) buried dead bodies
(B) Homo neanderthalensis (ii) able to stand upright on two legs
(C) Australopithecus (iii) made tools with stones using their hands
(D) Homo erectus (iv) The skeletal structure confirms bipedalism
Answer: (b) A : iii, B : i, C : iv, D : ii....
Question 9: Complete the table by including the following in appropriate columns.
| Lamarckism | Darwinism |
|---|---|
| Use and Disuse | Natural selection |
| Variations acquired in the life span | Only long necked giraffes survive |
| Through continuous use, giraffe's neck elongates | Inheritance of variations |
Chapter 3: Behind Sensations
Question 1: Which of the following statements is correct?
a. Each taste bud has different chemoreceptors.
b. Opsin in rhodopsin contains retinal which is formed from vitamin A.
c. Photoreceptors are formed from optic nerve.
d. Both rhodopsin and photopsin contain retinal.
Answer: Both b) and d) are supported by the text.
Question 5: Correct the mistake, if any. Impulses are formed in the retina due to the dissociation of rod cells.
Answer: The mistake is that the formation of impulses
is more directly related to chemical changes, not just dissociation.
Impulses are formed in the retina due to variations in glutamate production (the primary neurotransmitter in photoreceptors), which is controlled by the presence or absence of light.
Question 6: Analyse the given word pairs below, and find the relationship between them.
Question 8: Which part of the eye helps in focusing the light towards the retina
a) Cornea
b) Pupil
c) Lens
d) Iris
Answer: c) Lens.
Question 9: What is the main function of a neuron?
a) Protects organs
b) Exchange electric signals
c) Filters blood
d) Produce retinalin
Answer: b) Exchange electric signals.
Question 10: How does the arrangement of rod
cells and cone cells in the retina affect our ability to see in
different conditions of light? Why does this adaptation become
beneficial evolutionary?
Answer:
Question 11: How does the structure of the ear
enable it to convert the sound waves into signals that the brain can
interpret? How do damages in different parts of the ear affect hearing
and balance?
Answer:
Chapter 4: Chemoreception in Organisms
Question 1 (Abridged):
The illustration related to the transmission of hormones to their
target cells is given below. (A=Hormone, B=Receptor, C=Hormone-receptor
complex).
i. Write the function of A with respect to the formation of C.
Answer: The hormone (A) combines with its receptor (B)
to form the hormone-receptor complex (C). This complex then controls
activities inside the cell.
ii. If A is the releasing hormone, where can B be found?
Answer: Releasing hormones (produced by the
hypothalamus) stimulate the production of tropic hormones. Therefore,
the receptor (B) for the releasing hormone (A) would be found on the
target cells of the anterior lobe of the pituitary gland.
iii. How does the secretion and transmission of A differ in plants and animals?
Answer:
Question 2: The illustration given below is
related to the regulation of calcium level in blood. (Normal 9 - 11
mg/dL. Decreases → Parathormone (Increases); Increases →
............(1)........... (Decreases))
(a) Which hormone is indicated as 1?
Answer: Calcitonin.
Question 4:
Is it possible to sleep during the day just as one can sleep at night?
Justify your opinion by relating it to the functions of the pineal
gland.
Answer: While sleep is physiologically possible during
the day, the quality of sleep is hormonally optimized at night. The
pineal gland produces melatonin, the secretion of which
influences sleep and wakefulness. Melatonin production increases in
darkness (at night) and decreases during the day. Since darkness is
necessary for melatonin to be produced in the required quantity for
quality sleep, sleeping at night is generally better regulated by the
body's natural biological clock.
Question 5: The hypothalamus functions as part of the nervous system and the endocrine system. Evaluate the statement.
Answer: The statement is correct.
Question 6: ‘A person runs very fast and escapes from a ferocious dog’. This incident involves the functions listed below. Write them in the correct sequence.
Question 7 (Abridged): Information about a chemical substance is provided in the box:
Question 8: X, Y, and Z are the functions of
different plant hormones. X: Helps to tide over unfavourable situtation;
Y: Delays senescence of leaves and retains the greenness in that; Z:
Prevents the growth of the lateral bud. Choose the correct option.
i) Gibberellin, Ethylene, Abscisic acid
ii) Auxin, Abscisic acid, Gibberellin
iii) Abscisic acid, Cytokinin, Auxin
iv) Cytokinin, Gibberellin, Ethylene
Answer: iii) Abscisic acid, Cytokinin, Auxin.
Question 9: Explain how the pancreas regulates the amount of glucose in the blood in the following situations.
Answer: The pancreas (Islets of Langerhans) regulates blood glucose using insulin (from beta cells) and glucagon (from alpha cells).
Chapter 5: Immunity and Healthcare
Question 1: From the sequence of activities related to phagocytosis, select the correct answer.
(a) Expulsion of waste materials
(b) Engulfment of pathogens in phagosome
(c) Enzymes destroy the pathogen
(d) Phagocyte approaches the pathogen
(e) Phagolysosome is formed
Answer: ii) d, b, e, c, a.
Question 3: Which of the following is the correct pair of phagocytes?
Question 4: Analyse the given table and find the one in which both the statement and the reason are correct.
| Sl No. | Statement | Reason |
|---|---|---|
| (ii) | Blood clotting is a defence mechanism. | Prevents the flow of blood as well as blocks the entry of pathogens when there is a wound. |
| Answer: (ii). |
Question 5: From the following, select the statements that are correct, regarding vaccines:
Question 7: Analyse the table showing certain
pathogens in an area and the number of people affected by them and
answer the questions. (Pathogens: Naegleria fowleri 23, Leptospira 12,
Plasmodium 57, Filarial worm 35)
i) Which disease affected more people in the region?
Answer: Plasmodium (Malaria), with 57 infected people.
ii) Which bacterial disease affected the people?
Answer: Leptospira (Rat fever/Leptospirosis), with 12 infected people.
iii) Which pathogen affected the residents who bathed in stagnant fresh water?
Answer: Naegleria fowleri (causes amoebic encephalitis), which is mainly found in stagnant and warm fresh water.
Question 8: Give reasons. Although antibiotics are effective medicines, their irrational use is harmful.
Answer: Unscientific and excessive use of antibiotics is harmful because it leads to several negative consequences:
Chapter 6: Biology and Technology
Question 1: Which of the following statements about recombinant DNA technology is correct?
I. Restriction enzymes are used to cut the DNA of an organism.
II. Ligase enzymes join the cut DNA fragments together.
III. Vectors are usually bacterial plasmids.
IV. When recombinant DNA enters a host cell, it does not replicate.
Answer: b) I, II, III only.
Question 2: Identify A, B, and C and choose the correct option.
A: A technology that joins together DNA segments from two or more different organisms
B: A technology used to locate genes in DNA
C: A technology used to identify individuals by analysing the arrangement of nucleotides in DNA
Answer: i) A - Recombinant DNA Technology, B - Gene Mapping, C - DNA Fingerprinting....
Question 3:
What is the importance of the host cell in recombinant DNA technology?
Analyse how this technology would be limited if there were no host
cells.
Answer:
Question 4: Analyse how the information
provided by the Human Genome Project will help in the future development
of recombinant DNA technology, CRISPR editing technology and AI in
biology.
Answer: The Human Genome Project (HGP) provided crucial
foundational information, including the exact sequence of the 300 crore
base pairs in the human genome and the location of genes. This detailed
knowledge aids future technologies...:
Question 6: Analyse the fundamental similarities and differences between recombinant DNA technology and gene therapy.
Answer:
Question 7: Observe the illustration and answer the questions. (Illustration shows Guide RNA (A) leading Cas9 enzyme (B) to target DNA).
a) Name the technology indicated in the illustration.
Answer: CRISPR technology.
c) What is the role of A and B?
Answer:
Question 8 (Abridged): Explain how the
perpetrator can be identified by analysing a DNA fingerprinting report
in a forensic case. How can this technology be used to identify the
unidentified dead bodies found in natural disasters?
Answer:
Question 9: How does artificial intelligence (AI) help data analysis and discoveries in biological research?
Answer: AI plays a major role in biological study by handling and interpreting complex data:
Chapter 1: Genetics of Life
Question 1: Are basic building blocks of DNA and RNA the same? Explain.
Answer: The basic building blocks, called nucleotides, are not entirely the same1.
• A DNA nucleotide is composed of a deoxyribose sugar, a phosphate
group, and a nitrogen base (Adenine, Thymine, Guanine, or Cytosine)2.
• An RNA nucleotide is composed of a ribose sugar, a phosphate group,
and a nitrogenous base (Adenine, Uracil, Guanine, or Cytosine)1.
• While both share the phosphate group, they differ in two components:
DNA uses deoxyribose sugar, whereas RNA uses ribose sugar; and DNA uses
Thymine, whereas RNA uses Uracil12.
Question 2: Analyse the statements and choose the appropriate one.
i. F1 has similarity with both the parents. ii. F1 has no similarity
with any of the parents’ character intermediate to them. iii. F1 has
similarity with one of the parents
Answer: c) i - Co-dominance, ii - Incomplete dominance, iii - Dominance3.
• Co-dominance (i): Both alleles exhibit their traits at the same time (e.g., Roan coat pattern)4.
• Incomplete Dominance (ii): The dominant allele cannot fully hide the recessive allele, resulting in an intermediate trait45.
• Dominance (iii): When contrasting traits are hybridised, only one trait (the dominant one) is expressed in the F1 generation6.
Question 3: Which of the following is contributed by organisms that reproduce sexually, to their offspring?
a) All genes b) Half of their genes c) One fourth of their genes d) Double the number of genes
Answer: b) Half of their genes7.
• A pair of chromosomes forms a homologous chromosome, with one
inherited from the mother and the other from the father8. Sexual
reproduction involves the transmission of factors (genes) through
gametes910, each gamete carrying half the genetic constitution.
Question 4 (Abridged): A tall pea plant with purple flowers (dominant
character) is crossed with a dwarf plant with white flowers.
b) Did characters that differ from the parents appear in the F2
generation? Why? Answer: Yes, characters that differed from the parental
plants (e.g., tall with white flowers, dwarf with purple flowers)
appeared in the F2 generation511. This occurs because when two or more
different traits are combined, each trait is inherited independently to
the next generation without mixing12.
Question 5: How does dominance, co-dominance and incomplete dominance differ from one another?
Answer: These inheritance patterns differ based on how the traits are expressed in the hybrid (F1) generation4...:
• Dominance: Only the dominant trait is expressed in the F1 generation, and the recessive trait remains hidden6.
• Incomplete Dominance: The F1 offspring express a trait that is
intermediate to the parents because the dominant allele cannot fully
hide the recessive allele (e.g., red and white flowers yielding pink
flowers)45.
• Co-dominance: Both alleles exhibit their traits at the same time in the F1 offspring (e.g., the Roan coat pattern in cattle)4.
Question 7: Even though a gene responsible for certain characters has
more than two alleles, why does that particular gene have only two
alleles in an individual?
Answer: While a gene may exhibit Multiple Allelism (meaning the gene
pool of the human population, for example, has more than two alleles,
such as IA, IB, and i for blood group determination), an individual
organism inherits only two alleles for that character, one from each
parent4....
Question 8: Although the DNA possesses all genetic information for
protein synthesis, RNA is also required for protein synthesis. Why?
Answer: RNA is crucial because the process of protein synthesis involves multiple steps requiring different types of RNA113:
Chapter 2: Paths of Evolution
Question 2: Although dolphins have a larger brain than that of humans,
the level of thinking, language skills and social relationships are
higher in humans. Evaluate this statement based on the following
indicators:
• Difference in the structure of the brain
• Influence of natural selection
Answer:
• Difference in the structure of the brain: Human superiority in complex
thinking is attributed to the neocortex, the cerebral cortex of the
brain16. In mammals, the cerebral cortex is modified into a complex,
six-layered neocortex, which is more developed in humans compared to
other mammals16. The neocortex facilitates advanced mental processes
like thinking, decision-making, learning, recalling, and social
interaction1617.
• Influence of Natural Selection: The increase in brain capacity (which
nearly tripled over two million years) is a major trend in human
evolution18. This development facilitated complex social behaviour, the
ability to make tools, use language, and perform higher-level cognitive
functions18. This enhanced ability to adapt to changing environments and
develop culture and advanced technologies was naturally selected,
laying the foundation for the transition to Homo sapiens18.
Question 3: Redraw the figure of the neuron and label the following parts by writing their names.
(a) The part of the neuron that receives impulses from the adjacent
neuron (b) Part that contains neurotransmitter (c) Part that acts as
insulator
Answer: (a) The part of the neuron that receives impulses from the
adjacent neuron is the Dendrites (branches of the Dendrons)19. (b) The
part that contains neurotransmitter is the Synaptic knob (seen at the
tip of the axonite)1920. (c) The part that acts as an insulator is the
Myelin sheath (which is made up of a shiny white fat and increases the
speed of transmission of messages)21.
Question 4: Darwin failed to explain the reasons of variation even
though he argued that variations occur continuously in organisms.
Evaluate this statement based on the findings of Neo Darwinism.
Answer: The statement is valid as Charles Darwin did not have knowledge
regarding the genetic basis of variations and inheritance22. Neo
Darwinism addressed this limitation by incorporating later discoveries,
such as those made by Gregor Mendel, about chromosomes and genes22. Neo
Darwinism recognizes that the causes of variations that lead to
evolution are genetic changes (mutations), genetic recombination during
sexual reproduction, and gene flow2223.
Question 5: Observe the illustration and answer the questions.
(Illustration shows Central Nervous System (A) connected to body parts
via nerves (B)).
(a) Identify the nerves A and B. Answer: A: Central Nervous System
(Includes Brain and Spinal Cord)24. B: Peripheral Nervous System
(Includes cranial nerves, spinal nerves, receptors, and nerve ganglia
that connect the central nervous system to the organs)2425.
(b) Are messages being exchanged between A and B? Explain. Answer: Yes,
messages are continuously exchanged between the Central Nervous System
(A) and the Peripheral Nervous System (B)24. The spinal cord (part of A)
transmits messages from different parts of the body (via B) to the
brain, and transmits instructions from the brain (via A) to different
parts of the body (via B)26.
Question 6: A table that includes the parts of spinal cord and their
functions is given below. Arrange column B appropriately in accordance
with column A of the table.
A. Part
B. Functions/ Peculiarities
Central canal
Fluid present here nourishes the spinal cord2426
White matter
Neurons with myelin sheath are numerous27
Dorsal root
Transmits impulses to the spinal cord (messages from the body)26
Grey matter
Cell body of neurons are numerous (also parts of neurons without myelin sheath)27
Question 7: Based on the information obtained from fossils, some human
ancestors and their characteristics are given below. Find out the one
which is arranged correctly from the given answers.
(A) Homo habilis (i) buried dead bodies (B) Homo neanderthalensis (ii)
able to stand upright on two legs (C) Australopithecus (iii) made tools
with stones using their hands (D) Homo erectus (iv) The skeletal
structure confirms bipedalism
Answer: (b) A : iii, B : i, C : iv, D : ii28....
• (A) Homo habilis (iii) made tools with stones using their hands29.
• (B) Homo neanderthalensis (i) buried dead bodies31.
• (C) Australopithecus (iv) The skeletal structure confirms bipedalism29.
• (D) Homo erectus (ii) able to walk upright on two legs30.
Question 9: Complete the table by including the following in appropriate columns.
• Only long necked giraffes survive
• Use and Disuse
• Natural selection
• Variations acquired in the life span
• Through continuous use, giraffe's neck elongates
• Inheritance of variations
Lamarckism
Darwinism
Use and Disuse32
Natural selection3334
Variations acquired in the life span32
Only long necked giraffes survive35
Through continuous use, giraffe's neck elongates35
Inheritance of variations34
Chapter 3: Behind Sensations
Question 1: Which of the following statements is correct?
a. Each taste bud has different chemoreceptors. b. Opsin in rhodopsin
contains retinal which is formed from vitamin A. c. Photoreceptors are
formed from optic nerve. d. Both rhodopsin and photopsin contain
retinal.
Answer: Both b) and d) are supported by the text3637.
• b) Opsin in rhodopsin contains retinal which is formed from vitamin A:
The pigment rhodopsin (in rod cells) includes a protein (opsin) and
retinal, which is formed from Vitamin A36.
• d) Both rhodopsin and photopsin contain retinal: The components of
both rod cell pigment (rhodopsin) and cone cell pigment (photopsin)
include a protein (opsin) and retinal, formed from Vitamin A36.
Question 5: Correct the mistake, if any. Impulses are formed in the retina due to the dissociation of rod cells.
Answer: The mistake is that the formation of impulses is more directly
related to chemical changes, not just dissociation. Impulses are formed
in the retina due to variations in glutamate production (the primary
neurotransmitter in photoreceptors), which is controlled by the presence
or absence of light38.
Question 6: Analyse the given word pairs below, and find the relationship between them.
• Retinal - Night blindness
• Umami - Taste buds
• Cone cells - Colour Blindness
Answer:
• Retinal - Night blindness: Retinal is formed from Vitamin A36. Night
blindness is a condition caused by the deficiency of Vitamin A39.
• Umami - Taste buds: Umami is one of the main tastes recognized40.
Taste buds contain the chemoreceptors responsible for sensing taste40.
• Cone cells - Colour Blindness: Cone cells provide vision in intense
light and help in recognising colours3641. Colour blindness is caused by
defects in the genes responsible for the production of pigments in cone
cells42.
Question 8: Which part of the eye helps in focusing the light towards the retina
a) Cornea b) Pupil c) Lens d) Iris
Answer: c) Lens43.
• The convex lens forms a small, real, and inverted image of the object
accurately on the retina44. The eye adjusts the curvature of the lens to
achieve the power of accommodation (focusing near/distant objects)45.
Question 9: What is the main function of a neuron?
a) Protects organs b) Exchange electric signals c) Filters blood d) Produce retinalin
Answer: b) Exchange electric signals43.
• Neurons (nerve cells) are specialized cells capable of receiving
stimuli and forming suitable messages (nerve impulses), which are
electrical signals/charges4647.
Question 10: How does the arrangement of rod cells and cone cells in the
retina affect our ability to see in different conditions of light? Why
does this adaptation become beneficial evolutionary?
Answer:
• Ability to See: The retina contains two types of photoreceptors36:
◦ Rod cells: Are numerous (over 9 crores) and contain rhodopsin. They
recognize objects in dim light and in shades of black and white36.
◦ Cone cells: Are fewer (about 45 lakhs) and contain photopsin. They
provide vision in intense light and help in recognizing colours3641.
• Evolutionary Benefit: This arrangement ensures that the organism can
perceive the environment effectively across a wide range of light
conditions, enabling both nocturnal and daylight activity, which is
crucial for survival and adaptation48.
Question 11: How does the structure of the ear enable it to convert the
sound waves into signals that the brain can interpret? How do damages in
different parts of the ear affect hearing and balance?
Answer:
• Conversion of Sound Waves: Sound waves are directed by the pinna into
the auditory canal and vibrate the tympanum (eardrum)4950. These
vibrations are amplified and transmitted through the ear ossicles
(malleus, incus, stapes) to the oval window5051. The oval window
transmits vibrations to the fluids (perilymph and endolymph) within the
cochlea50. The fluid movement stimulates the hair cells located in the
Organ of Corti (on the basilar membrane), generating impulses50. These
impulses travel through the auditory nerve to the brain, resulting in
the sense of hearing50.
• Effect of Damages:
◦ Hearing: Damage to the tympanum, ear ossicles, oval window, or the
structures within the cochlea (Organ of Corti, hair cells) would impair
the transmission or generation of impulses, affecting hearing5051.
◦ Balance: The vestibular system (including three semicircular canals,
utricle, and saccule in the vestibule) is responsible for maintaining
body balance4952. Damage here would inhibit the formation of impulses
related to the head's linear or rotational movement, thereby impairing
balance52.
Chapter 4: Chemoreception in Organisms
Question 1 (Abridged): The illustration related to the transmission of
hormones to their target cells is given below. (A=Hormone, B=Receptor,
C=Hormone-receptor complex).
i. Write the function of A with respect to the formation of C. Answer:
The hormone (A) combines with its receptor (B) to form the
hormone-receptor complex (C)53. This complex then controls activities
inside the cell54.
ii. If A is the releasing hormone, where can B be found? Answer:
Releasing hormones (produced by the hypothalamus) stimulate the
production of tropic hormones55. Therefore, the receptor (B) for the
releasing hormone (A) would be found on the target cells of the anterior
lobe of the pituitary gland5355.
iii. How does the secretion and transmission of A differ in plants and animals? Answer:
• Animals (Hormones): Produced by endocrine glands and transmitted to target cells through blood54.
• Plants (Hormones): Produced at locations like the tip of the shoot or
root, seeds, or sprouting leaves. They reach target cells via
cell-to-cell transport or through xylem and phloem54.
Question 2: The illustration given below is related to the regulation of
calcium level in blood. (Normal 9 - 11 mg/dL. Decreases → Parathormone
(Increases); Increases → ............(1)........... (Decreases))
(a) Which hormone is indicated as 1? Answer: Calcitonin5657.
Question 4: Is it possible to sleep during the day just as one can sleep
at night? Justify your opinion by relating it to the functions of the
pineal gland.
Answer: While sleep is physiologically possible during the day, the
quality of sleep is hormonally optimized at night58. The pineal gland
produces melatonin, the secretion of which influences sleep and
wakefulness59. Melatonin production increases in darkness (at night) and
decreases during the day. Since darkness is necessary for melatonin to
be produced in the required quantity for quality sleep, sleeping at
night is generally better regulated by the body's natural biological
clock58.
Question 5: The hypothalamus functions as part of the nervous system and the endocrine system. Evaluate the statement.
Answer: The statement is correct60.
• Nervous System Role: The hypothalamus is located in the brain,
functioning to maintain homeostasis (e.g., regulating body temperature,
hunger, thirst)61. It uses neurosecretory cells to produce hormones55.
• Endocrine System Role: The hypothalamus is considered the master
controller of the hormone production process60. It controls the
functioning of most endocrine glands by regulating the production of
tropic hormones secreted by the anterior lobe of the pituitary
gland5560.
Question 6: ‘A person runs very fast and escapes from a ferocious dog’.
This incident involves the functions listed below. Write them in the
correct sequence.
• Action of adrenal gland
• Action of the sympathetic nervous system
• Action of parasympathetic nervous system
Answer:
Chapter 5: Immunity and Healthcare
Question 1: From the sequence of activities related to phagocytosis,
select the correct answer. (a) Expulsion of waste materials (b)
Engulfment of pathogens in phagosome (c) Enzymes destroy the pathogen
(d) Phagocyte approaches the pathogen (e) Phagolysosome is formed
Answer: ii) d, b, e, c, a73.
• (d) Phagocyte approaches the pathogen74.
• (b) Engulfment of pathogens in phagosome74.
• (e) Phagolysosome is formed75.
• (c) Enzymes destroy the pathogen7475.
• (a) Expulsion of waste materials74.
Question 3: Which of the following is the correct pair of phagocytes?
• Eosinophil, Neutrophil
• Neutrophil, Monocyte
• Basophil, Neutrophil
• Monocyte, Lymphocyte
Answer: Neutrophil, Monocyte73.
• Neutrophils and monocytes are the white blood cells that participate
in phagocytosis (the process of engulfing and destroying pathogens)7476.
Question 4: Analyse the given table and find the one in which both the statement and the reason are correct.
Sl No.
Statement
Reason
(ii)
Blood clotting is a defence mechanism.
Prevents the flow of blood as well as blocks the entry of pathogens when there is a wound.
Answer: (ii)77.
• Blood clotting is a mechanism that prevents blood flow and blocks the
entry of pathogens into the body when a wound forms on the skin, thus
functioning as an immune mechanism7879.
Question 5: From the following, select the statements that are correct, regarding vaccines:
• Vaccines act as antigens.
• The immunity produced by vaccines is innate immunity.
• Vaccines help to produce antibodies against pathogens.
• All vaccines contain deactivated pathogens.
Answer: The correct statements are:
Chapter 6: Biology and Technology
Question 1: Which of the following statements about recombinant DNA technology is correct?
I. Restriction enzymes are used to cut the DNA of an organism. II.
Ligase enzymes join the cut DNA fragments together. III. Vectors are
usually bacterial plasmids. IV. When recombinant DNA enters a host cell,
it does not replicate.
Answer: b) I, II, III only86.
• I. Restriction Endonuclease Enzyme is known as genetic scissors that cuts a specific gene87.
• II. Ligase enzyme (genetic glue) joins two DNA segments87.
• III. Plasmids (circular DNA in bacteria) are used as gene vectors87.
• (IV is incorrect; the new recombinant DNA must become active in the host cell to replicate and form the desired product)88.
Question 2: Identify A, B, and C and choose the correct option.
A: A technology that joins together DNA segments from two or more
different organisms B: A technology used to locate genes in DNA C: A
technology used to identify individuals by analysing the arrangement of
nucleotides in DNA
Answer: i) A - Recombinant DNA Technology, B - Gene Mapping, C - DNA Fingerprinting87....
Question 3: What is the importance of the host cell in recombinant DNA
technology? Analyse how this technology would be limited if there were
no host cells.
Answer:
• Importance: The host cell is where the recombinant DNA (formed by
ligating the desired gene into a vector, like a plasmid) is inserted88.
Once inserted, the genes become active, and the host cell multiplies,
thereby producing the desired products (e.g., insulin)88.
• Limitation: If there were no host cells, the technology would be
severely limited because the recombinant DNA could not be replicated,
multiplied, or expressed to produce the desired products or traits in
large quantities88.
Question 4: Analyse how the information provided by the Human Genome
Project will help in the future development of recombinant DNA
technology, CRISPR editing technology and AI in biology.
Answer: The Human Genome Project (HGP) provided crucial foundational
information, including the exact sequence of the 300 crore base pairs in
the human genome and the location of genes9092. This detailed knowledge
aids future technologies93...:
• CRISPR Technology: HGP data allows researchers to precisely identify
the specific DNA segment (target) that needs to be cut or edited96.
• Recombinant DNA Technology: HGP knowledge aids in the precise
identification of desirable genes necessary to cut, ligate, and insert
into vectors8792.
• AI in Biology: AI relies on analyzing large amounts of genetic data
(Bioinformatics)9495. HGP data enables AI to predict disease causes,
suggest new treatment methods, and design personalized medicine based on
an individual’s genetic makeup92....
Question 6: Analyse the fundamental similarities and differences between recombinant DNA technology and gene therapy.
Answer:
• Similarities: Both technologies fundamentally involve altering the
genetic makeup of an organism9798. Both aim to introduce or utilize
functional genes to achieve a desired outcome9798.
• Differences:
◦ Recombinant DNA Technology typically focuses on combining DNA segments
from two or more organisms, often utilizing host cells (like bacteria)
for large-scale production of a product (e.g., insulin)8788.
◦ Gene Therapy is a specific medical application where defective genes
in a patient are removed and replaced with functional genes to treat a
disease98.
Question 7: Observe the illustration and answer the questions.
(Illustration shows Guide RNA (A) leading Cas9 enzyme (B) to target
DNA).
a) Name the technology indicated in the illustration. Answer: CRISPR technology99.
c) What is the role of A and B? Answer:
• A (Guide RNA or gRNA): It precisely identifies the DNA segment that needs to be cut (Identifying the target)96100.
• B (Cas9 enzyme): It acts as the genetic scissors that cuts the DNA segment identified by the guide RNA96100.
Question 8 (Abridged): Explain how the perpetrator can be identified by
analysing a DNA fingerprinting report in a forensic case. How can this
technology be used to identify the unidentified dead bodies found in
natural disasters?
Answer:
• Identifying the Perpetrator: DNA fingerprinting analyzes the unique
sequence and pattern of nucleotides, particularly the repeated sequences
in the "junk DNA" part, which vary significantly between
individuals101. In a forensic case, the DNA pattern obtained from the
sample (hair, blood, or saliva) at the scene of the crime is compared
with the DNA patterns of suspects. A match confirms the identity of the
culprit101102.
• Identifying Dead Bodies: This technology is utilized to identify
victims of accidents or disasters because an individual’s DNA pattern is
unique, like a fingerprint91102. The unidentified body's DNA pattern
can be compared to known DNA patterns of immediate family members
(parents or offspring) to determine the biological relationship and thus
establish the identity102.
Question 9: How does artificial intelligence (AI) help data analysis and discoveries in biological research?
Answer: AI plays a major role in biological study by handling and interpreting complex data95:
• Bioinformatics: AI analyzes large amounts of genetic data, assisting
in sequencing and suggesting simplification strategies9495.
• Personalised Medicine: AI analyzes an individual's genetic makeup and
health information to recommend the most suitable treatment regimens94.
• Drug Discovery and Treatment: AI is used for discovering new drugs,
predicting the effectiveness of chemical substances, and assisting in
disease diagnosis and treatment recommendations93.write without page
reference numbers
SCERT X Standard Physics: Questions and Answers
Chapter 1: Sound Waves
Solved Numerical Problems
Let's Assess Questions
Chapter 2: Lenses
Solved Numerical Problems
Let's Assess Questions
5. A concave lens has a focal length of 50 cm. What will be its power?
* a) +2 D b) +0.5 D c) −2 D d) −0.5 D
* Calculation derived from source concepts: f = −0.5 m. P = 1/f = 1/(−0.5) = −2 D.
Chapter 3: The World of Colours and Vision
Let's Assess Questions
2. Which of the following pairs of colours can produce white light?
* a) magenta, blue b) yellow, green c) red, green d) magenta, green
* Note: This is based on complementary colours. Magenta (R+B) + Green = White.
3. Fill in the blanks appropriately:
* a) Cyan colour + Red → white light
* b) Blue colour + Yellow → white light
* c) Magenta colour + green colour → white light
* d) Magenta colour + cyan colour + yellow colour → Dark
Chapter 5: Electric Energy: Consumption and Conservation
Solved Numerical Problems
Let's Assess Questions (Numerical problems requiring explicit calculation steps based on given values)
Chapter 6: Electromagnetic Induction in Daily Life
Solved Numerical Problems
Let's Assess Questions (Selected with explicit answers/classification)
Chapter 7: Mechanical Advantage in Action
Solved Numerical Problems
Let's Assess Questions
SCERT X Standard Physics: Questions and Answers
Chapter 1: Sound Waves
Solved Numerical Problems
Chapter 2: Lenses
Solved Numerical Problems
Chapter 3: The World of Colours and Vision
Let's Assess Questions
2. Which of the following pairs of colours can produce white light?25
◦ a) magenta, blue b) yellow, green c) red, green d) magenta, green
◦ Note: This is based on complementary colours. Magenta (R+B) + Green = White.2627
3. Fill in the blanks appropriately:28
◦ a) Cyan colour + Red → white light29
◦ b) Blue colour + Yellow → white light29
◦ c) Magenta colour + green colour → white light29
◦ d) Magenta colour + cyan colour + yellow colour → Dark30
Chapter 5: Electric Energy: Consumption and Conservation
Solved Numerical Problems
Chapter 6: Electromagnetic Induction in Daily Life
Solved Numerical Problems
Let's Assess Questions (Selected with explicit answers/classification)
Chapter 7: Mechanical Advantage in Action
Solved Numerical Problems
Chapter 1: Genetics of Life
I. Introduction to Genetics and Gene Editing
II. The Structure and Location of DNA
III. Chromosome Structure and Types
IV. Genes and Protein Synthesis
V. Principles of Inheritance (Mendel)
VI. Non-Mendelian Inheritance and Variation Sources
Chapter 2: Paths of Evolution
I. Evolution and Early Theories
II. Speciation and Evidences of Evolution
III. Human Evolution
IV. The Nervous System
Chapter 3: Behind Sensations
I. Stimuli, Receptors, and Senses
II. Vision (The Eye)
III. Hearing and Balance (The Ear)
IV. Smell, Taste, and Touch
Chapter 4: Chemoreception in Organisms
I. Hormones and General Function
II. Plant Hormones
III. Regulation in Humans
Chapter 5: Immunity and Healthcare
I. Immunity Mechanisms
II. Diseases and Pathogens
III. Healthcare and Blood
Chapter 6: Biology and Technology
I. Genetic Engineering Technologies
II. Genomics and Gene Therapy
III. Modern Biology and Environmental Technology
Chapter 1: Genetics of Life1
I. Introduction to Genetics and Gene Editing
• Gene Editing involves methodologies to bring desirable changes in the genes in DNA2.
• The Nobel Prize in Chemistry (2020) was shared by Emmanuelle
Charpentier and Jennifer A Doudna for the discovery of CRISPR-Cas 9, a
gene editing technology2.
• CRISPR-Cas 9 is expected to make revolutionary advances in genetic
disease therapy and cancer treatment, and can also be used to develop
crops resistant to pests and diseases2.
• A deeper understanding of DNA (Deoxyribonucleic acid) and genes paved the way for gene editing3.
II. The Structure and Location of DNA
• Location: DNA is found within the chromosomes inside the cell nucleus34.
• Discovery: James Watson and Francis Crick presented the double helical
model of DNA in 1953, based on X-ray diffraction studies, including the
crucial image 'Photo 51' taken by Rosalind Franklin5.
• DNA Structure:
◦ It is composed of two strands6.
◦ The strands are made up of sugar (deoxyribose) and phosphate molecules6.
◦ The structure resembles a double helix6.
◦ Nucleotide: This is the basic building block of DNA, composed of a
deoxyribose sugar (a 5-carbon sugar), a phosphate group, and a nitrogen
base46.
◦ Nitrogen Bases: Adenine, Thymine, Guanine, and Cytosine4.
◦ Rungs (formed by paired bases) link the strands6.
◦ Pairing Mode: Nitrogen base pairing forms the rungs: Adenine pairs with Thymine (A-T), and Guanine pairs with Cytosine (G-C)6.
III. Chromosome Structure and Types
• Chromosome Components: DNA and histone proteins are the primary components7.
• Nucleosome Formation: Eight histone proteins join to form a histone
octamer7. DNA strands wind around this octamer to form a nucleosome7.
• Chromosome Formation: Chromosomes are formed by the packing, coiling, and recoiling of numerous nucleosomes7.
• Chromatids: These are parts of a chromosome connected by a centromere78.
• Human Chromosomes:
◦ Humans have a specific number of chromosomes8.
◦ Somatic chromosomes: Control physical characteristics9. There are
twenty-two pairs of somatic chromosomes9. A pair of identical
chromosomes forms a homologous chromosome (one inherited from each
parent)9.
◦ Sex Chromosomes: Involved in sex determination9. They are X chromosome and Y chromosome9.
▪ The Y chromosome is comparatively smaller than the X chromosome9.
▪ The SRY gene on the Y chromosome is responsible for the development of testis in the embryo9.
◦ Normal Genetic Constitution: Female: 44 + XX; Male: 44 + XY10.
◦ Variant Genetic Constitutions: Examples include Turner syndrome
(44+X0), Triple-X syndrome (44+XXX), Klinefelter syndrome (44+XXY), and
XYY syndrome (44+XYY). These influence physical and mental
development1011.
IV. Genes and Protein Synthesis
• Gene: A gene is a specific sequence of nucleotides in DNA12. Proteins
are synthesized according to gene instructions and are responsible for
forming characteristics and controlling metabolic activities12.
• RNA (Ribonucleic acid): Another type of nucleic acid involved in protein synthesis13.
◦ It is made up of nucleotides containing a ribose sugar, a phosphate
group, and nitrogenous bases (Adenine, Guanine, Uracil, and Cytosine)13.
◦ Most RNAs have a single strand13.
• Stages of Protein Synthesis:
1. Transcription: mRNA (messenger RNA) is formed from a specific
nucleotide sequence (gene) in DNA, carrying messages for protein
synthesis14. This process takes place in the nucleus15.
2. Translation: tRNAs (transfer RNA) carry specific amino acids to the
ribosome15. rRNAs (ribosomal RNA), which are part of the ribosomes,
combine amino acids to make protein15. This process takes place in the
cytoplasm15.
V. Principles of Inheritance (Mendel)
• Heredity: The transmission of characteristics from parents to offspring16.
• Variations: Characters expressed in offspring that differ from their parents16.
• Genetics: The branch of science dealing with genes, heredity, and variation17.
• Gregor Johann Mendel (Father of Genetics) laid the foundation for the
field through experiments on pea plants (Pisum sativum)17. His
conclusions are known as the Laws of Inheritance18.
• Terminology:
◦ Factors: Hypothetical units (now known as genes) transmitted through gametes that determine a character19.
◦ Alleles: Different forms of a gene19.
◦ Phenotype: The observable characteristics of an organism19.
◦ Genotype: The genetic constitution responsible for the characteristics19.
• Monohybrid Cross (Single Trait):
◦ Inference: When a pair of contrasting traits is hybridised, only one
(the dominant trait) is expressed in the first generation (F1), while
the other (recessive trait) remains hidden20. The hidden trait reappears
in the second generation (F2)20.
◦ Law of Segregation: When gametes are formed, the factors (alleles) that determine the trait get separated without mixing21.
◦ The ratio of dominant to recessive traits in the F2 generation is 3:121.
• Dihybrid Cross (Two Traits):
◦ Mendel’s Postulate (Law of Independent Assortment): When two or more
different traits are combined, each trait is inherited independently to
the next generation without mixing; one pair of alleles does not
influence the separation of another pair22.
VI. Non-Mendelian Inheritance and Variation Sources
• Non-Mendelian Inheritance: Explains traits resulting from complex
interactions among genes, environment, and other factors, limiting the
explanation provided solely by Mendel’s laws22.
◦ Incomplete Dominance: A dominant allele cannot fully hide the
recessive allele23. The offspring expresses a character intermediate to
the parents (e.g., pink flowers from red x white)2425.
◦ Co-dominance: Both alleles exhibit their traits at the same time23.
The F1 generation shows similarity with both parents (e.g., Roan coat
pattern, ABO blood group)2325.
◦ Multiple Allelism: The gene that determines a character has more than
two alleles (e.g., ABO blood group determined by IA, IB, and i)23.
◦ Polygenic Inheritance: More than one gene controls the character (e.g., difference in skin colour)23.
• Genetic Processes Responsible for Variations:
◦ Crossing Over: Occurs during the first phase of meiosis26. Homologous
chromosomes pair up27. Chromatids break at the point of contact
(chiasma) and exchange segments, causing a recombination of alleles27.
This leads to the appearance of new traits in the offspring27.
◦ Mutation: A sudden, heritable change in the genetic constitution of an
organism28. It can be caused by errors during DNA replication, exposure
to certain chemicals, or radiations28. Mutations change genes, are
transferred through generations, and play a crucial role in evolution28.
Chapter 2: Paths of Evolution1
I. Evolution and Early Theories
• Antibiotic Resistance: Resistance in bacteria (e.g., tuberculosis
bacteria) is caused by a mutation in a specific gene29. The mutated
bacteria multiply even in the presence of antibiotics29. Over time,
through further mutations, they acquire the ability to resist multiple
antibiotics, leading to multi-drug-resistant strains (superbugs)30.
• Lamarckism (Theory of Inheritance of Acquired Characters): Initiated by Jean Baptiste Lamarck31.
◦ Idea: Organisms adapt to changes, and characters acquired during their
lifetime (e.g., giraffe stretching its neck to reach high leaves) are
transmitted through generations, leading to the emergence of new
species3132.
◦ Limitation: Later scientists proved that acquired characters do not
impart change in the genetic structure of organisms and are thus not
inherited32.
• Darwinism (The Theory of Natural Selection): Proposed by English
naturalist Charles Darwin33. It marked the foundation for modern
evolutionary perspectives and was published in On the Origin of Species
(1859)34.
• Key Concepts of Natural Selection:
1. Over Production: Organisms produce more offspring than the environment can support35.
2. Variations: Organisms exhibit differences (size, immunity, etc.) that can be favourable or harmful35.
3. Struggle for existence: Competition among organisms due to limited resources (food, shelter, mates)35.
4. Survival of the fittest: Organisms with favourable variations survive
the struggle, reproduce more effectively, and produce new
generations36.
5. Natural Selection: Favourable variations are passed on and accumulate
over time, leading to the creation of new species that cannot reproduce
within the original species36.
• Neo Darwinism: A rationalised theory developed after incorporating
discoveries of Gregor Mendel and concepts of chromosomes and genes37. It
recognized that the causes of variation are genetic changes, genetic
recombination during sexual reproduction, and gene flow37.
II. Speciation and Evidences of Evolution
• Speciation: The process in which new species arise from a common ancestor38.
◦ LUCA (Last Universal Common Ancestor): Thought to be the ancestor of all species38.
◦ MRCA (Most Recent Common Ancestor): The ancestor shared by different species38.
◦ Speciation occurs when members of a population become isolated (by
ecological or other factors like mutation/natural selection), accumulate
variations over time, and eventually become unable to reproduce
mutually39.
• Evidences of Evolution:
◦ Molecular Biology: Comparing the sequence of nucleotides in DNA or
amino acids in proteins40. For example, the beta chain of haemoglobin
shows 0 difference between humans and chimpanzees, suggesting the
closest evolutionary relationship4041.
◦ Comparative Anatomy: Similarities in the internal structure of
different organisms validate evolution42. Homologous structures, like
the forelimbs of humans, cats, whales, and bats, are similar internally
but differ in external structure and function43.
◦ Fossil Evidences: Remains or traces of ancient organisms44. They show
that organic evolution is a gradual process (e.g., ancestors of horses
had shorter legs) and reveal connecting links (e.g., Archaeopteryx
possessing features of both reptiles and birds)44.
III. Human Evolution
• Primate Characteristics: Humans, monkeys, and apes belong to the group
of primates45. Common features include a thumb that can be opposed to
other fingers and binocular vision45.
• Evolutionary Trend: A major trend in human evolution is the increase
in brain capacity, which nearly tripled over two million years4647. This
enabled complex social behaviour, tool making, language use, and
higher-level cognitive functions47.
• Key Ancestors (with Cranial Capacity):
◦ Sahelanthropus tchadensis (350 cm3): First link in human evolutionary series4648.
◦ Astralopethecus (450 cm3): Skeletal structure confirms bipedalism (walking on two legs)4648.
◦ Homo habilis (600 cm3): Made tools with stones using hands46....
◦ Homo erectus (900 cm3): Able to walk upright on two legs; used excellent stone weapons46....
◦ Homo neanderthalensis (1450 cm3): Contemporaries of modern man; buried dead bodies46....
◦ Homo sapiens (1350 cm3): Modern man; acquired technology, agriculture, built cities51.
IV. The Nervous System
• Role: The nervous system controls and coordinates the vital functions of the body52.
• Components: Brain, spinal cord, nerves, and receptors52.
• Neuron (Nerve Cells): Basic building blocks; specialised cells capable of receiving stimuli and forming messages52.
◦ Cell body (Cyton): Center of the neuron53.
◦ Dendrites/Dendrons: Fine fibres/branches that receive messages from adjacent neurons and transmit them to the cyton53.
◦ Axon: The longest fibre from the cell body53.
◦ Axonites: Branches of the axon53.
◦ Synaptic knob: Knob-like structure at the tip of the axonite; contains
a neurotransmitter (e.g., Acetylcholine) to transfer chemical
messages53.
• Neuroglial cells: More than half of the brain and spinal cord cells54.
They cannot receive stimuli or transmit messages54. Functions include
bringing nutrition, eliminating wastes, and acting as defence cells54.
• Myelin Sheath: A layer covering some axons, made up of shiny white fat (Myelin)55.
◦ Functions: Increases the speed of message transmission (acts as an insulator), provides nourishment, and protects the axon55.
◦ Formation: Produced by oligodendrocytes (in brain/spinal cord) and Schwann cells (in nerves)55.
◦ Matter: White matter is where myelinated neurons are abundant; grey
matter is where cell bodies and parts without myelin sheath are seen56.
• Protection of CNS (Brain and Spinal Cord):
◦ Covered by the three-layered Meninges57.
◦ Cerebrospinal Fluid (CSF): Fills the space between the inner membranes
of the meninges, the brain cavities, and the central canal of the
spinal cord57. Functions include providing oxygen/nutrients, eliminating
wastes, regulating pressure, and protecting from external injuries58.
• Divisions of Nervous System:
1. Central Nervous System (CNS): Includes the Brain and Spinal cord58.
2. Peripheral Nervous System (PNS): Includes 12 pairs of cranial nerves
and 31 pairs of spinal nerves, receptors, and nerve ganglia5859.
• Brain Functions:
◦ Cerebrum: Largest part60. Centre of memory, intelligence, thinking, imagination, and voluntary movements60.
◦ Cerebellum: Second largest part; maintains equilibrium by coordinating muscular activities61.
◦ Thalamus: Acts as the relay station of messages to and from the cerebrum61.
◦ Hypothalamus: Helps in maintaining homeostasis by regulating body temperature, hunger, thirst, and emotions61.
◦ Medulla Oblongata: Controls involuntary activities like heartbeat, ventilation, vomiting, cough, and sneezing59.
• Nerve Impulse Transmission: Messages are transmitted as nerve impulses62.
◦ Unstimulated neuron: Outer surface is positively charged; inner surface is negatively charged63.
◦ Stimulation: Positive ions enter the cell, causing a temporary charge variation62.
• Synapse: The part where an impulse is transferred from one neuron to another64.
◦ The synaptic knob secretes neurotransmitters into the synaptic cleft
(gap), which bind to the receptors of the post-synaptic membrane,
stimulating the next neuron65.
◦ Synapses transmit impulses in only one direction and increase their speed65.
◦ Neocortex: The complex, six-layered cerebral cortex, highly developed
in humans. Its synapses enable advanced mental processes like thinking
and decision-making66.
• Types of Neurons (by function):
◦ Sensory neuron: Transmits impulses from receptors to CNS67.
◦ Motor neuron: Transmits instructions from CNS to organs (muscles/glands)67.
◦ Inter neuron: Found between neurons, helping in central processing66.
• Autonomous Nervous System (ANS): Part of the PNS that regulates body activities by itself68.
◦ Sympathetic system: Prepares the body for emergency situations (e.g., dilates pupil, increases heartbeat)6869.
◦ Parasympathetic system: Prepares the body to relax and perform routine
functions (e.g., constricts pupil, decreases heartbeat, stimulates
digestion)6869.
• Reflex Actions: Reactions that occur spontaneously and involuntarily
in response to stimuli70. They can originate from the spinal cord or the
brain70.
◦ Reflex Arc: The pathway through which impulses are transmitted:
Receptor → Sensory neuron → Inter neuron (often in spinal cord) → Motor
neuron → Muscle/Gland70.
Chapter 3: Behind Sensations1
I. Stimuli, Receptors, and Senses
• Stimuli: Circumstances that lead to responses in living beings (external or internal)71.
• Sensory Receptors: Specialised cells or nerve endings that recognise stimuli72.
• Impulse Formation: Stimuli cause electrical impulses called Receptor
potential72. If the concentration of these impulses is high, Action
potential is formed in the associated neurons, which travels as a nerve
impulse72.
• Types of Senses:
◦ General Senses: Detected by receptors in skin, muscles, joints, internal organs (e.g., touch, pain, heat, pressure)73.
◦ Special Senses: Detected by receptors concentrated only in certain organs (e.g., vision, hearing, taste, smell)73.
II. Vision (The Eye)
• Protective Mechanisms: Eyelid, eyelashes, tears74. Tears are produced
by lacrimal glands and contain the enzyme lysozyme to protect from
infections74.
• Conjunctiva: A membrane covering the anterior part of the eye (except cornea); keeps it moist and lubricated75.
• Layers of the Eye:
1. Sclera (Outer Layer): Provides firmness and protection76.
2. Choroid (Middle Layer): Provides oxygen and nutrients to the retina; regulates temperature. Contains the Iris76.
3. Retina (Inner Layer): Contains photoreceptor cells; where the image is formed77.
• Associated Parts:
◦ Cornea: Transparent anterior part; allows light to enter76.
◦ Iris: Contains melanin pigment; regulates the amount of light entering
the eye by adjusting the size of the Pupil (the aperture at its
centre)76....
◦ Lens: A convex lens that forms a small, real, and inverted image on the retina77. Attached to Ciliary muscles by ligaments80.
◦ Power of Accommodation: The ability of the eye to focus images of both
near and distant objects accurately on the retina by changing the
curvature of the lens80.
• Eye Chambers and Humors:
◦ Aqueous chamber: Between cornea and lens; contains watery Aqueous
humor (provides O2/nutrients to lens/cornea, regulates pressure)81.
◦ Vitreous chamber: Between lens and retina; contains jelly-like Vitreous humor (maintains the shape of the eyeball)78.
• Photoreceptors (in Retina): Both types contain pigments composed of opsin and retinal (formed from Vitamin A)82.
◦ Rod Cells: More numerous (9+ crores); contain Rhodopsin. Recognise objects in dim light and shades of black and white7782.
◦ Cone Cells: Less numerous (45 lakh); contain Photopsin. Provide vision in intense light and help recognise colours7782.
◦ Vision Centre: The yellow spot (macula) is where cone cells are
abundant81. The blind spot is where the optic nerve originates, lacking
photoreceptors81.
◦ Impulse Transmission: In the dark, photoreceptors continuously produce
the neurotransmitter Glutamate83. In the presence of light, glutamate
production stops, activating 'on bipolar cells' which send impulses via
ganglion cells to the optic nerve7784.
• Binocular Fusion: The brain compares the two slightly different images
received from both eyes and combines them, resulting in 3D vision and
depth perception85.
• Disorders: Short-sightedness (enlarged eyeball), Cataract (opaque
lens), Glaucoma (increased pressure due to failure of aqueous humor
reabsorption), Night blindness (Vitamin A deficiency)86.
III. Hearing and Balance (The Ear)
• Main Parts: Outer ear, Middle ear, Inner ear87.
◦ Outer Ear: Pinna (directs sound waves) and Auditory canal (protects tympanum, contains hair/wax)88.
◦ Middle Ear: Tympanum (eardrum) vibrates with sound89. Ear ossicles
(Malleus, Incus, Stapes) transmit vibrations89. Eustachian canal
connects to the pharynx and balances air pressure on both sides of the
tympanum90.
◦ Inner Ear: Includes the Cochlea (hearing) and the Vestibular system (balance)8791.
• Mechanism of Hearing:
◦ Vibrations travel from the tympanum → ear ossicles → oval window92.
◦ Cochlea: Snail-shaped, has three chambers. Upper/lower chambers contain Perilymph; middle chamber contains Endolymph92.
◦ Organ of Corti: Located in the basilar membrane92. Contains auditory
receptors (hair cells) that generate impulses when vibrated92. Impulses
reach the brain through the auditory nerve92.
• Mechanism of Balance:
◦ Involves the vestibular system in the inner ear: three semicircular
canals and the vestibule (containing utricle and saccule)91.
◦ Endolymph moves with head rotation, stimulating hair cells in the canals and vestibule91.
◦ Impulses travel through the vestibular nerve to the brain (cerebellum)93.
• Hearing Impairment: Caused by noise intensity above 80 decibels; loud
noise (>85 dB) for a short time or less intense noise (<55 dB) for
a very long time can cause permanent impairment94.
IV. Smell, Taste, and Touch
• Olfaction (Smell):
◦ Particles responsible for smell dissolve in the mucus produced by the mucus membrane in the nasal cavity95.
◦ Millions of olfactory neurons (receptors) get stimulated95.
◦ Impulses travel through the olfactory nerve to the brain95.
• Taste:
◦ Detected by Chemoreceptors located in Taste buds, which are found in the Papilla of the tongue96.
◦ Substances dissolve in saliva and stimulate the chemoreceptors96.
◦ Main tastes recognised: sweet, sour, salty, pungent, bitter, and umami96.
• Skin Receptors (Touch/Pain): The skin contains various specialised receptors9798.
◦ Nocireceptors (Independent nerve endings): Specialised receptors that identify pain9899.
◦ Merkel disc/Meissner corpuscles: Detect touch and pressure98.
◦ Pacinian corpuscles: Detect vibration and high-frequency touch98100.
Chapter 4: Chemoreception in Organisms101
I. Hormones and General Function
• Definition: Hormones are chemical substances that regulate and coordinate body functions alongside the nervous system102.
• Target Cells: A cell in which a hormone acts103. Each target cell has receptors suitable for that hormone103.
• Mechanism: Hormones combine with receptors to form a hormone-receptor complex, which controls activities inside the cell104.
• Transport: Animal hormones (from endocrine glands) reach target cells
through the blood104. Plant hormones move via cell-to-cell transport or
through xylem/phloem104.
II. Plant Hormones
• Auxin: Discovered by F W Went105106. Stimulates cell elongation,
increases stem length, inhibits lateral bud growth, and regulates tropic
movements107108. Tends to stay away from light, causing bending
(phototropism)107109.
• Gibberellins: Break seed dormancy; influence fruit and seed growth; stimulate cell division in stems and roots108110.
• Cytokinins: Stimulate cell division and differentiation; stimulate
lateral bud growth; delay senescence and retain the green colour of
leaves108.
• Ethylene: Plays a role in the ageing of leaves/flowers and the ripening of fruits110.
• Abscisic Acid (ABA): Inhibits the growth of plant parts; maintains
seed dormancy until favourable conditions arise; enables plants to tide
over unfavourable conditions110.
• Photoperiodism: The response of plants to the duration of day and
night, regulating flowering time111. Involves Phytochrome, a
light-sensitive pigment synthesized in fully developed leaves111.
III. Regulation in Humans
• Thyroid Gland (Metabolism):
◦ Thyroxine (from Follicular cells): Controls metabolism, body
temperature, brain development in children, and maintains health of
heart/skin/reproductive system112.
◦ Calcitonin (from Parafollicular cells): Reduces the level of calcium in the blood112.
◦ Disorders: Hyperthyroidism (excessive thyroxine), Hypothyroidism (reduced thyroxine), and Goitre (swelling in the neck)113.
• Regulation of Calcium (Normal: 9-11 mg/dL): Maintained by the combined
action of Calcitonin and Parathormone (from the parathyroid gland)114.
◦ When calcium is high, Calcitonin inhibits its release from bones115.
◦ When calcium is low, Parathormone stimulates its release from bones and increases reabsorption from the blood115116.
• Pancreas (Glucose Regulation):
◦ Islets of Langerhans: Contain Alpha cells (produce Glucagon) and Beta cells (produce Insulin)117.
◦ Insulin Action (when glucose level increases): Speeds up glucose entry
into cells; promotes glucose → glycogen conversion in the liver118.
◦ Glucagon Action (when glucose level decreases): Promotes glycogen →
glucose conversion in the liver; promotes glucose synthesis from amino
acids119.
◦ Diabetes Mellitus: Blood glucose level rises above normal (FBS >
126 mg/dL)119. Type 1 (loss of insulin production due to beta cell
destruction)120. Type 2 (variation in insulin production or decreased
effectiveness)120.
• Adrenal Gland (Emergency): Works with the sympathetic nervous system121.
◦ Medulla: Secretes Epinephrine (adrenaline) and Norepinephrine122.
These increase heart rate/blood pressure/blood glucose, preparing the
body for emergency122.
◦ Cortex: Produces corticosteroids (Glucocorticoids like Cortisol,
Mineralocorticoids like Aldosterone, and Gonadocorticoids)123.
▪ Cortisol resists inflammation, suppresses immune responses, and maintains glucose homeostasis123.
• Pineal Gland (Sleep): Produces Melatonin124. Variations in secretion
influence sleep and wakefulness; the gland is known as the biological
clock124125.
• Hypothalamus and Pituitary (Master Control):
◦ Hypothalamus: Master controller126. Controls pituitary function by
producing Releasing and Inhibitory hormones that regulate tropic hormone
production in the anterior lobe127.
◦ Pituitary Anterior Lobe: Secretes tropic hormones (TSH, ACTH, GTH) and Somatotropin (GH) (growth hormone)128129.
◦ Pituitary Posterior Lobe: Stores and secretes Vasopressin (ADH) (water
reabsorption in kidney) and Oxytocin (smooth muscle contraction,
lactation)128130.
• Growth Disorders: Caused by Somatotropin variations129. Dwarfism
(decreased GH during growth phase), Gigantism (increased GH during
growth phase), Acromegaly (increased GH after growth phase)131.
• Pheromones: Chemical substances secreted by organisms into the
surroundings for communication with the same species132. Examples
include: Territorial, Aggregation, Alarm, Trail, and Sex pheromones133.
Chapter 5: Immunity and Healthcare101
I. Immunity Mechanisms
• Health: A complete state of physical, mental, and social well-being134.
• Antigen: Anything (pathogens, pollen, chemicals) that enters the body and causes disease135.
• Immunity: The body's ability to prevent the entry of pathogens and destroy those already inside136.
◦ Innate Immunity (Non-specific): Natural, present by birth, acts irrespective of the type of pathogen137138.
▪ Primary Level: Physical and chemical barriers (e.g., Lysozyme in
tears/saliva, Mucus membrane, HCl in stomach, Wax in ear)137139.
▪ Secondary Level: Defence mechanisms if pathogens enter:
• Phagocytosis: Phagocytes (e.g., Neutrophils and Monocytes) engulf and destroy pathogens140141.
• Inflammatory Response: Blood vessels dilate due to histamine release;
increased blood flow brings white blood cells to the injured area142.
• Fever: Increased body temperature (above 98.6°F) triggered by
pyrogens143. It enhances phagocytosis and inhibits pathogen growth143.
• Blood Clotting: Prevents blood loss and blocks pathogen entry144.
Involves thromboplastin converting prothrombin to thrombin, and thrombin
converting fibrinogen to fibrin threads144.
◦ Acquired Immunity (Specific): Develops after birth; specifically recognises antigens138. Carried out by Lymphocytes145.
▪ T Lymphocytes: Form in bone marrow, mature in the thymus gland. Destroy infected cells and cancer cells146.
▪ B Lymphocytes: Form and mature in the bone marrow. Produce proteins called antibodies147.
• Artificial Immunity (Vaccination): Immunisation is an artificial method to prepare immune cells148.
◦ Vaccines: Act as antigens, stimulating the immune system to produce
antibodies for long-term protection149150. Edward Jenner is known as the
father of vaccination147.
II. Diseases and Pathogens
• Acquired Diseases: Occur during life (communicable or non-communicable)151.
• Transmission: Direct contact, contaminated food/water, surfaces, coughing/sneezing (droplets)152.
• Bacterial Diseases: Bacteria release toxins or enzymes that destroy
host tissues152. Examples: Rat fever (Leptospira), Tuberculosis
(Mycobacterium tuberculosis)153154.
• Viral Diseases: Viruses multiply using the host cell's genetic
mechanism, destroying the cells155. Examples: AIDS (HIV attacks T
lymphocytes, reducing immunity)156, Nipah157.
• Fungal Diseases: Fungi infect skin/nails or produce toxins. Examples: Ringworm, Candidiasis158.
• Protozoan Diseases: Unicellular eukaryotes. Example: Malaria
(Plasmodium, transmitted by Anopheles mosquito, destroys red blood
cells)159160. Amoebic encephalitis (Naegleria fowleri)161.
• Worm Infestations: Caused by parasitic worms (e.g., pin worm, round
worm)162. Filariasis is caused by filarial worms transmitted by Culex
mosquitoes, which lodge in lymphatic vessels and cause swelling163.
• Non-Contagious Diseases:
◦ Cancer: Abnormal and uncontrolled cell division164. Normal cells turn
into cancer cells when control mechanisms fail, spreading through
blood/lymph164.
◦ Hereditary Diseases (Genetic Defects): Sickle cell anaemia (defective
gene for haemoglobin, causes sickle-shaped RBCs)165. Haemophilia
(defective gene for blood clotting proteins)166.
III. Healthcare and Blood
• Treatment Systems: Ayurveda (traditional Indian system, focus on
balance, diet, herbs)167. Homeopathy (uses diluted doses of natural
substances)168. Modern Medicine (focus on diagnosis, pathogens, surgery,
organ transplantation)168169.
• Antibiotics: Medicines used against bacteria, derived from
microorganisms or synthesized170. Revolutionary (Penicillin discovered
by Alexander Fleming, 1928)171. Excessive use leads to side effects and
Antibiotic resistance170171.
• Blood Groups: Determined by the presence of A antigen and B antigen on the surface of RBCs172.
◦ Rh factor: Determined by the presence (positive) or absence (negative) of the D antigen172.
◦ Blood group matching is essential for transfusion because antibodies
in the recipient's plasma may act against donor antigens, causing
agglutination172.
Chapter 6: Biology and Technology101
I. Genetic Engineering Technologies
• Biotechnology: Technology using living things or their parts to provide useful products and services for humans173.
• Genetic Engineering: Technology used for creating desired traits in organisms by combining or deleting genes173.
• Recombinant DNA Technology: Combines DNA segments from two or more different organisms174. Requires:
◦ Restriction Endonuclease Enzyme: Acts as genetic scissors, cutting specific genes174.
◦ Ligase Enzyme: Acts as genetic glue, joining DNA segments174.
◦ Vector: Carries genes (e.g., bacterial plasmids or some viruses)174.
◦ Host Cell: Where the recombinant DNA is inserted and becomes active (e.g., production of human insulin using bacteria)175.
• CRISPR Technology (Gene Editing): Modern technology used to edit DNA with great precision176.
◦ Uses Cas9 enzyme as scissors to cut DNA177.
◦ Uses a Guide RNA (gRNA) that precisely identifies the DNA segment to be cut177178.
◦ Allows removal of unwanted characteristics or addition of new ones177.
• Genetically Modified Organisms (GMOs): Plants, animals, or
microorganisms whose genetic constitutions have been altered through
genetic engineering179. Examples include Bt. Cotton (pest resistance),
Golden rice (nutrient-enriched), and E. coli (insulin production)180.
II. Genomics and Gene Therapy
• Genome: The sum total of all the genetic materials in an organism181.
• Human Genome Project (HGP): A global initiative (1990–2003) to
sequence and understand the human genome (approximately 300 crore DNA
base pairs)181. It used Gene Mapping to identify gene locations181.
• HGP Findings: Humans have 20,000 to 25,000 genes; only 1–2% of the genome consists of functional genes182.
• Gene Therapy: The method of treating diseases by removing defective genes and replacing them with functional genes183.
◦ Somatic gene therapy: Delivers healthy genes to body cells; genetic changes are not passed on to the next generation184.
◦ Germline gene therapy: Transfers genes into reproductive cells;
genetic changes are transmitted to future generations (raises ethical
questions)184.
• DNA Fingerprinting: Discovered by Sir Alex Jeffrey (1984)185.
◦ Basis: While 99.9% of DNA is the same, variations in the remaining
0.1% (especially in repeated sequences in non-coding regions) are unique
to each individual186.
◦ Uses: To identify culprits, determine biological relationships
(parents/offspring), identify genetic disorders, and track endangered
species187.
III. Modern Biology and Environmental Technology
• Human Microbiome Project (HMP): Launched in 2007, studying the
collection of microorganisms (bacteria, fungi, viruses) and their genes
that inhabit the human body188. This community provides services like
immunity, digestion, and vitamin production188.
◦ Faeces to Medicine: Beneficial bacteria collected from healthy faeces
("poop pills") are used to treat drug-resistant bacterial infections189.
• Biology and Artificial Intelligence (AI): AI plays a major role in biological study190.
◦ Applications: Diagnosis, drug discovery, personalised medicine
(analysing genetic makeup), improving agriculture (monitoring
soil/predicting crop diseases), pollution prediction, and genome
sequencing191192.
◦ Bioinformatics: A scientific discipline that analyses large amounts of
biological data by combining computer science, mathematics, and
statistics190.
• Technologies for Environmental Conservation:
◦ Cryopreservation: Preserving living cells/tissues at very low temperatures (-196°C) for long-term preservation193.
◦ Bioremediation: Uses microorganisms and plants to remove pollutants from contaminated environments194.
◦ Wildlife Tracking/Data Sensors: Utilising sensors and satellite remote
sensing to monitor biodiversity and animal movement for conservation
planning193.write without page reference numbers
Unit 1: Nomenclature of Organic Compounds and Isomerism
The embedded exercises in this unit primarily involve naming structures or drawing formulae based on IUPAC rules.
I. Activity: Functional Group Identification
Complete the table:
| Functional group | Name of functional group | Common name |
|---|---|---|
| −OH | Hydroxyl | Alcohol |
| −COOH | Carboxyl | Carboxylic acid |
| −CHO | Aldehydic | Aldehyde |
| C=O | Keto | Ketone |
| −O–R | Alkoxy | Ether |
| −F,−Cl,−Br,−I | Halo | Halo compounds |
II. Let us assess...
Question 5: i) CH₃–CH₂–O–CH₂–CH₃ ii) CH₃–CH₂–CH₂–CH₂–OH
a) What type of isomerism do these compounds exhibit?
b) Write the structural formula of the metamer of compound (i).
Answer:
a) They have the same molecular formula (C₄H₁₀O) but different functional groups (Ether and Alcohol). They exhibit Functional isomerism.
b) Metamers have the same molecular formula but different alkyl groups
attached to either side of the functional group (O or C=O). Structural
formula of the metamer of (i) (Ethoxyethane): CH₃–O–CH₂–CH₂–CH₃ (Methoxypropane).
Question 6: i) CH₃–CH₂–CH₂–CH₂–CHO ii) CH₃–CH₂–CH₂–CO–CH₃
a) What is the IUPAC name of the first compound?
b) These two compounds are isomers. Why?
c) What type of isomerism do these compounds exhibit?
d) Write the structural formula of the position isomer of the second compound.
Answer:
a) The main chain has 5 carbon atoms including the aldehyde group (CHO). IUPAC name: Pentanal.
b) They are isomers because they have the same molecular formula
(C₅H₁₀O) but different structural formulae and hence different chemical
and physical properties.
c) They have the same molecular formula but different functional groups (Aldehyde in (i), Ketone in (ii)). They exhibit Functional isomerism.
d) Compound (ii) is Pentan-2-one (Keto group at C₂). A position isomer
would be Pentan-3-one (Keto group at C₃). Structural formula: CH₃–CH₂–CO–CH₂–CH₃.
Question 7: Examine the compounds given below and identify the isomeric pairs. What type of isomerism is shown by each pair?
a) Methoxypropane
b) 2,3–Dimethylbutane
c) Propan–1–ol
d) Ethoxyethane
e) Propan–2–ol
f) Hexane
Answer:
Unit 2: Chemical Reactions of Organic Compounds
I. Let us assess...
Question 1:
a) In which of the following situation is methane converted to chloromethane? (i) Chlorine + sunlight
b) Write the name of such types of reactions.
Answer:
a) (i) Chlorine + sunlight.
b) Substitution reactions.
Question 2:
a) How many hydrogen molecules are required to convert CH≡CH (ethyne) into C₂H₆ (ethane)?
b) Write the chemical equation of the reaction.
c) To which category does this chemical reaction belong?
Answer:
a) Two hydrogen molecules are required (C₂H₂ + 2H₂ → C₂H₆).
b) H–C≡C–H + 2H₂ → CH₃–CH₃.
c) Addition reactions.
Question 4:
a) Which of the given polymers is used to coat the inner surface of cookware? (Polythene, polyvinyl chloride, teflon).
b) What is the monomer of this polymer?
Answer:
a) Teflon (Polytetrafluoroethene).
b) Monomer: Tetrafluoroethene (CF₂=CF₂).
Question 5:
a) Which among the following is a condensation polymer? (Polyvinyl chloride, nylon 66, teflon).
b) What are the monomers of nylon 66?
Answer:
a) Nylon 66.
b) Monomers: Adipic acid (HOOC–(CH₂)₄–COOH) and Hexamethylenediamine (NH₂–(CH₂)₆–NH₂).
Question 6:
C₁₂H₂₂O₁₁ + H₂O --(A)--> C₆H₁₂O₆(B) + C₆H₁₂O₆(C)
C₆H₁₂O₆ --(D)--> 2C₂H₅OH + 2CO₂
a) Identify A,B,C and D in the given chemical reactions.
b) What is wash?
c) How is rectified spirit obtained from wash?
d) What is the purpose of denaturing rectified spirit?
Answer:
a) A = Invertase (enzyme); B = Glucose; C = Fructose; D = Zymase (enzyme).
b) Wash is the 8%–10% ethanol solution obtained after the fermentation of molasses.
c) Rectified spirit (95.6% ethanol) is obtained when wash is subjected to fractional distillation.
d) Denaturing rectified spirit involves adding toxic substances (like
methanol or pyridine) to ethanol to prevent its misuse as a beverage.
Question 7:
a) How is ethanoic acid prepared industrially?
b) 5%–8% ethanoic acid is called ...................
Answer:
a) Ethanoic acid is prepared industrially by treating methanol (CH₃OH) with carbon monoxide (CO) in the presence of a catalyst.
b) 5%–8% ethanoic acid is called vinegar.
Question 8:
CH₃–COOH + CH₃–OH --(conc. H₂SO₄)--> CH₃–COO–CH₃ + H₂O
a) What is the name of this chemical reaction?
b) What is the name of the ester formed?
c) Write any two uses of esters.
Answer:
a) Esterification.
b) The ester formed is Methyl ethanoate (from ethanoic acid and methanol).
c) Esters are used to make artificial perfumes and juices because they possess the fragrance of flowers and fruits.
Unit 3: Periodic Table and Electron Configuration
I. Let us assess...
Question 1: The element X having 3 shells belongs to group 17.
a) Write the subshell electron configuration of this element.
b) To which block does this element belong?
c) What is its period number?
d) Write the molecular formula of the compound formed when X reacts with
an atom of element Y which belongs to the third period and has one
electron in its p subshell.
Answer:
a) Element X is in period 3 (3 shells) and group 17 (p-block). It must
have 7 outermost electrons (2 in s and 5 in p subshells). Subshell
electron configuration: 1s²2s²2p⁶3s²3p⁵. (Cl)
b) p-block (since the last electron is added to the p subshell).
c) 3 (The highest shell number is 3).
d) Element Y is in period 3 and has 1 electron in its p subshell.
Outermost configuration: 3s²3p¹. This element is in Group 13 (2 + 10 + 1
= 13). (Aluminium, Al). Element X (Cl) has oxidation state −1. Element Y
(Al) has oxidation state +3. Molecular formula: YX₃ (e.g., AlCl₃).
Question 2: A few subshells are given. 3p, 4d, 3f, 2d, 2p.
a) Among these, which subshells are not possible?
b) Explain the reason.
Answer:
a) The subshells that are not possible are 3f and 2d.
b) The Azimuthal quantum number (l) defines subshells and its value ranges from 0 to (n−1).
Question 7: Which subshell is represented by each pair of the quantum number values given below?
a) n=1, l=0
b) n=2, l=1
Answer:
a) n=1, l=0: 1s subshell (where l=0 denotes the s subshell).
b) n=2, l=1: 2p subshell (where l=1 denotes the p subshell).
Question 10: Iron (Fe) takes part in chemical reactions and becomes Fe³⁺ ion. (Atomic number of Fe=26).
a) Write the electron configuration of this ion.
b) Write the chemical formula of the compound formed when this ion combines with sulphate ion (SO₄²⁻).
c) Which is the other oxidation state of this element? Write the electron configuration of the ion thus formed.
d) Iron shows variable oxidation states. Why?
Answer:
a) Neutral Fe configuration: 1s²2s²2p⁶3s²3p⁶3d⁶4s². To form Fe³⁺, three
electrons are lost: two from the outermost 4s subshell and one from the
3d subshell. Fe³⁺ electron configuration: 1s²2s²2p⁶3s²3p⁶3d⁵.
b) The Fe³⁺ ion combines with SO₄²⁻ ion. Chemical formula: Fe₂(SO₄)₃.
c) The other common oxidation state is +2 (Ferrous). The ion formed is Fe²⁺ (loses two 4s electrons). Electron configuration of Fe²⁺: 1s²2s²2p⁶3s²3p⁶3d⁶.
d) Iron (a transition element) shows variable oxidation states because
there is only a slight energy difference between the outermost s subshell and the penultimate d subshell. As a result, electrons from the d subshell can also participate in chemical reactions under favourable conditions.
Unit 4: Gas Laws and Mole Concept
I. Activity: Calculation of Volume using Combined Gas Equation
Question: The volume of a gas at 27°C and 1 atm pressure is 100 mL. What will be its volume at 273 K temperature and 2 atm pressure?
Answer: Initial conditions: T₁ = 27°C = (27+273) K =
300 K; P₁ = 1 atm; V₁ = 100 mL. Final conditions: T₂ = 273 K; P₂ = 2
atm; V₂ = ?. Using the Combined Gas Equation: P₁V₁/T₁ = P₂V₂/T₂.
(1 × 100) / 300 = (2 × V₂) / 273
V₂ = (100 × 273) / (300 × 2) = 273 / 6 = 45.5 mL.
Volume at 273 K and 2 atm: 45.5 mL.
II. Let us assess
Question 2: Complete the table. (Atomic Mass - H=1, C=12, O=16, N=14).
| Substance | Molar Mass (g) | Given mass (g) | Number of moles | Volume at STP (L) |
|---|---|---|---|---|
| H₂ | 2 | 10 | 5 | 112 |
| CO₂ | 44 | 440 | 10 | 224 |
| NH₃ | 17 | 340 | 20 | 448 |
| (Derivations based on Number of moles = Given mass / Molar mass, and Volume at STP = Number of moles × 22.4 L): |
Question 5: 400 L of gas is stored in a cylinder at 27°C and constant pressure.
a) What will be the temperature if the volume of this gas is reduced to 200 L at the same pressure?
b) Which gas law is relevant to this context?
c) The boiling point of a substance is 3°C. Above what temperature in Kelvin does this substance obey the gas laws?
Answer:
a) This is governed by Charles’s Law (constant pressure). T₁ = 27°C = 300 K; V₁ = 400 L. T₂ = ?; V₂ = 200 L. V₁/T₁ = V₂/T₂.
400 / 300 = 200 / T₂
T₂ = (200 × 300) / 400 = 150 K.
b) Charles’s Law (At constant pressure, volume is directly proportional to temperature in Kelvin).
c) Gas laws describe the properties of gases. Since the boiling point is
3°C, the substance must be in the gaseous state above this temperature.
3°C = (3+273) K = 276 K. The substance obeys the gas laws above 276 K.
Unit 5: Electrochemistry
I. Conceptual Questions
Question: Why can silver nitrate solution not be stored in a copper vessel?
Answer: Copper is a more reactive metal than silver.
The more reactive metal (Copper) will displace the less reactive metal
(Ag⁺ ion) from its salt solution. The reaction is Cu + 2AgNO₃ → Cu(NO₃)₂
+ 2Ag, meaning the copper vessel would dissolve.
Question: Which of the following metals can displace hydrogen from hydrochloric acid? (Sodium, gold, silver, aluminium)
Answer: Sodium and Aluminium. The metals placed above hydrogen in the reactivity series can displace hydrogen from dilute acids.
Question: Define fuel cells and write its advantage.
Answer: Fuel cells are galvanic cells designed to
convert the chemical energy produced by the combustion of fuels (such as
hydrogen, methane, and methanol) directly into electrical energy. An
advantage is that they produce electricity with high efficiency.
II. Let us assess...
Question 1: Examine the diagram of a galvanic cell (Zn/Cu) and find out whether the given statements are true or false.
a) As the cell operates, the mass of the zinc rod, Zn(s) decreases.
b) The copper electrode is the anode.
c) Electrons flow from the zinc electrode to the copper electrode through the external circuit.
d) During cell reaction, reduction takes place at the copper electrode.
e) During cell reaction, the concentration of Cu²⁺ decreases.
Answer:
a) True (Oxidation occurs: Zn(s) → Zn²⁺(aq) + 2e⁻).
b) False (Zinc is the anode (oxidation), Copper is the cathode (reduction)).
c) True (Flow is from anode (Zn) to cathode (Cu)).
d) True (Reduction occurs at the cathode: Cu²⁺(aq) + 2e⁻ → Cu(s)).
e) True (Cu²⁺ ions are consumed to form Cu metal at the cathode).
Question 4: When an aqueous sodium chloride solution is electrolysed, the reaction that takes place at the anode is:
(i) Na⁺(aq) + e⁻ → Na(s)
(ii) 2H₂O(l) → 4H⁺(aq) + O₂(g) + 4e⁻
(iii) H⁺(aq) + e⁻ → ½H₂(g)
(iv) Cl⁻(aq) → ½Cl₂(g) + e⁻
Answer: (iv) Cl⁻(aq) → ½Cl₂(g) + e⁻ (Chloride ions are oxidised to chlorine gas at the anode).
Question 5: Write the products obtained when the following solutions undergo electrolysis.
(i) Aqueous solution of NaCl
(ii) Aqueous solution of CuSO₄ (using copper electrodes)
Answer:
(i) Products: H₂ gas (at cathode), Cl₂ gas (at anode), and an aqueous solution of NaOH.
(ii) The process is electrolytic refining. Products: The impure copper anode dissolves (Cu → Cu²⁺), and pure copper is deposited on the cathode (Cu²⁺ → Cu).
Question 6:
Brass is an alloy of zinc and copper. When brass comes into contact
with saline water, corrosion of metal takes place and zinc gradually
dissolves in the solution, leaving copper behind. Explain why zinc
dissolves in comparison to copper.
Answer: Zinc is more reactive than copper; this is
indicated by its higher position in the reactivity series. When two
metals are in contact in the presence of an electrolyte (like saline
water), the more reactive metal acts as the anode and is destroyed
(corrodes), thus protecting the less reactive metal (copper).
Unit 6: Metals
I. Conceptual Questions
Question: What are the qualities of a mineral which is used to extract a metal?
Answer: The mineral should have: Abundance, Ease of extraction, High metal content, and Low production cost.
Question: The nature of ores is given. Complete the table using appropriate concentration methods.
| Nature of ore | Concentration method |
|---|---|
| 1. Ores are less dense than the impurities. | Froth floatation |
| 2. Ores have magnetic properties but impurities are non magnetic. | Magnetic separation |
| 3. A solvent which dissolves the ore is used. | Leaching |
| 4. Ores are denser than the impurities. | Levigation (Hydraulic washing) |
Question: What type of flux should be used if the gangue in the ore is basic in nature?
Answer: An acidic flux should be used, as the flux combines with the gangue to form molten slag.
II. Let us assess...
Question 1: Define the following and answer the given questions.
(1) Ore - What is the ore of aluminium?
(2) Roasting - Which type of ores are subjected to roasting?
(3) Reducing agent - What is the reducing agent used in the manufacture of aluminium?
(4) Flux - Which flux is used in the manufacture of copper? Why?
(5) Leaching - Which metal ore is leached with sodium cyanide?
Answer:
(1) Ore: Any mineral from which a metal can be extracted easily and economically. Ore of aluminium: Bauxite (Al₂O₃·2H₂O).
(2) Roasting: Heating the concentrated ore at a temperature below the melting point in the presence of air. Ores subjected to roasting: Sulphide ores.
(3) Reducing agent for aluminium: Electricity (or e⁻).
(4) Flux used in copper manufacture: Sand (SiO₂). This is an acidic flux, and it is used because the ore contains basic impurities (such as iron oxide).
(5) Metal ores leached with sodium cyanide (NaCN): Gold and Silver ores.
Question 2: Find the relation and write the answer.
Zinc sulphide : Roasting :: Calcium carbonate : ....................
Magnetite : Magnetic separation :: Bauxite : ....................
Answer:
Question 4: Following are two facts related to the manufacture of an industrially important metal.
Question 6: Corrosion is a process by which iron is converted into its oxide. This is an oxidation reaction.
(i) What is oxidation?
(ii) Complete the following chemical equation. ....... Fe + ....... O₂ → ....... Fe₂O₃
(iii) Suggest two methods for preventing the corrosion of iron.
Answer:
(i) Corrosion (as an oxidation process): A process in which the metal reacts with its surrounding medium and undergoes chemical change.
(ii) 4Fe + 3O₂ → 2Fe₂O₃.
(iii) Two methods: Electroplating and Cathodic protection (e.g., attaching zinc or magnesium blocks to iron).
Question 7: Alloys containing iron are given. Find a,b,c,d.
| Alloys | Constituent elements | Uses |
|---|---|---|
| Alnico | (a) Fe, Al, Ni, Co | (b) Making of permanent magnets |
| Stainless steel | (c) Fe, Cr, Ni, C | Resist the corrosion of iron. Making of utensils |
| Silicon steel | Fe, Si, C | (d) Used in the core of electromagnetic instruments (e.g., motors, generators, transformers) as it reduces electric loss |
Unit 7: Some Compounds of Industrial Importance
I. Conceptual Questions
Question: Why is the jar used for collecting ammonia kept inverted?
Answer: Ammonia gas is less dense than atmospheric air.
Question: Why does the water entering the flask change its colour (to pink) in the ammonia fountain experiment?
Answer: Ammonia dissolves in water to form ammonium
hydroxide (NH₄OH), which is an alkaline substance (base).
Phenolphthalein is an indicator that gives a pink colour with alkaline
substances.
Question: Concentrated H₂SO₄ is not used as a drying agent in the preparation of NH₃. Why?
Answer: Concentrated H₂SO₄ and NH₃ react chemically.
Question: What are the essential qualities of fertilizers?
Answer:
II. Let us assess...
Question 1: Chemical formula of certain salts are given below: KCl, (NH₄)₂SO₄, AlCl₃, CH₃COONa. Choose the correct statements.
(i) KCl does not undergo hydrolysis.
(ii) (NH₄)₂SO₄ is an acidic salt.
(iii) AlCl₃ is a basic salt.
(iv) CH₃COONa is used to increase the basicity of an aqueous solution.
Answer:
Question 4: Explain with chemical equations of
the chemical reactions that take place in the left and right chambers of
the membrane cell during the chlor-alkali process.
Answer: This process involves the electrolysis of concentrated aqueous sodium chloride solution (brine).
| Chamber | Electrode | Reaction Type | Chemical Equation | Product(s) Formed |
|---|---|---|---|---|
| Left | Anode (+) | Oxidation | 2Cl⁻ → Cl₂ + 2e⁻ | Chlorine gas (Cl₂) |
| Right | Cathode (–) | Reduction | 2H₂O + 2e⁻ → H₂ + 2OH⁻ | Hydrogen gas (H₂) and Sodium Hydroxide (NaOH) |
Question 6: Explain the effect of pressure on the following reversible reactions.
(i) H₂(g) + I₂(g) ⇌ 2HI(g)
(ii) N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
Answer: Pressure affects equilibrium only if the number of gaseous molecules changes in the reaction.
(i) No effect: Total moles of reactants (H₂ + I₂) is 2;
total moles of product (2HI) is 2. Since the number of moles of gaseous
molecules does not change, pressure will have no effect on the chemical
equilibrium.
(ii) Pressure increases product yield: Total moles of
reactants (N₂ + 3H₂) is 4; total moles of product (2NH₃) is 2. According
to Le Chatelier’s principle, increasing pressure shifts the equilibrium
in the direction where the number of moles decreases. Thus, increasing
pressure favors the forward reaction, increasing the production of NH₃.
Question 7:
2NO(g) + O₂(g) ⇌ 2NO₂(g) + heat (Forward reaction is exothermic, 3
moles → 2 moles). Complete the table by indicating the possible measures
to increase the amount of NO₂ (product).
Answer:
| Change Applied | Effect on NO₂ Production | Reason (Le Chatelier’s Principle) |
|---|---|---|
| Temperature | Decrease | Favours the exothermic reaction (forward reaction). |
| Pressure | Increase | Favours the direction with fewer moles (forward reaction, 3 → 2). |
| Amount of oxygen | Increase | Increases reactant concentration, shifts equilibrium forward. |
| Amount of NO | Increase | Increases reactant concentration, shifts equilibrium forward. |
Question 11:
(i) Which substance is used as the drying agent in the laboratory preparation of ammonia?
(ii) Can concentrated sulphuric acid be used as a drying agent in this
process? Write the chemical equation that occurs if it is used.
Answer:
(i) The drying agent used is Quick lime (CaO).
(ii) Concentrated sulphuric acid cannot be used. This is because ammonia
(NH₃) reacts with concentrated sulphuric acid (H₂SO₄). The chemical
equation (implied reaction): 2NH₃ + H₂SO₄ → (NH₄)₂SO₄.
Question 12: Complete the table.
| Function in plants | Fertilizers that can be used |
|---|---|
| To accelerate plant growth. | Urea, sodium nitrate (Nitrogenous fertilizers) |
| To increase productivity. | Ammonium phosphate, potassium chloride (Phosphate and Potash fertilizers) |
| To boost immunity of plants. | Potassium chloride (Potash fertilizers) |
Unit 1: Nomenclature of Organic Compounds and Isomerism
The embedded exercises in this unit primarily involve naming structures or drawing formulae based on IUPAC rules.
I. Activity: Functional Group Identification1
Complete the table:
Functional group
Name of functional group
Common name
−OH
Hydroxyl1
Alcohol1
−COOH
Carboxyl1
Carboxylic acid1
−CHO
Aldehydic1
Aldehyde1
C=O
Keto1
Ketone1
−O–R
Alkoxy1
Ether1
−F,−Cl,−Br,−I
Halo1
Halo compounds1
II. Let us assess2...
Question 53: i) CH3–CH2–O–CH2–CH3 ii) CH3–CH2–CH2–CH2–OH a) What
type of isomerism do these compounds exhibit? b) Write the structural
formula of the metamer of compound (i).
Answer: a) They have the same molecular formula (C4H10O) but different
functional groups (Ether and Alcohol). They exhibit Functional
isomerism56. b) Metamers have the same molecular formula but different
alkyl groups attached to either side of the functional group (O or
C=O)78. Structural formula of the metamer of (i) (Ethoxyethane):
CH3–O–CH2–CH2–CH3 (Methoxymethane)7.
Question 634: i) CH3–CH2–CH2–CH2–CHO ii) CH3–CH2–CH2–CO–CH3 a)
What is the IUPAC name of the first compound? b) These two compounds are
isomers. Why? c) What type of isomerism do these compounds exhibit? d)
Write the structural formula of the position isomer of the second
compound.
Answer: a) The main chain has 5 carbon atoms including the aldehyde
group (CHO)9. IUPAC name: Pentanal9. b) They are isomers because they
have the same molecular formula (C5H10O) but different structural
formulae and hence different chemical and physical properties1011. c)
They have the same molecular formula but different functional groups
(Aldehyde in (i), Ketone in (ii))612. They exhibit Functional
isomerism6. d) Compound (ii) is Pentan-2-one (Keto group at C2). A
position isomer would be Pentan-3-one (Keto group at C3). Structural
formula: CH3–CH2–CO–CH2–CH31314.
Question 74: Examine the compounds given below and identify the isomeric
pairs. What type of isomerism is shown by each pair? a) Methoxypropane
b) 2,3–Dimethylbutane c) Propan–1–ol d) Ethoxyethane e) Propan–2–ol f)
Hexane
Answer:
Unit 2: Chemical Reactions of Organic Compounds
I. Let us assess17...
Question 117: a) In which of the following situation is methane
converted to chloromethane? (i) Chlorine + sunlight b) Write the name of
such types of reactions.
Answer: a) (i) Chlorine + sunlight21. b) Substitution reactions21.
Question 218: a) How many hydrogen molecules are required to convert
CH≡CH (ethyne) into C2H6 (ethane)? b) Write the chemical equation of
the reaction. c) To which category does this chemical reaction belong?
Answer: a) Two hydrogen molecules are required (C2H2+2H2→C2H6). 222. b) H–C≡C–H+2H2→CH3–CH322. c) Addition reactions23.
Question 41819: a) Which of the given polymers is used to coat the inner
surface of cookware? (Polythene, polyvinyl chloride, teflon). b) What
is the monomer of this polymer?
Answer: a) Teflon (Polytetrafluoroethene)24. b) Monomer: Tetrafluoroethene (CF2=CF2)24.
Question 519: a) Which among the following is a condensation polymer?
(Polyvinyl chloride, nylon 66, teflon). b) What are the monomers of
nylon 66?
Answer: a) Nylon 6625. b) Monomers: Adipic acid (HOOC–(CH2)4–COOH) and Hexamethylenediamine (NH2–(CH2)6–NH2)2526.
Question 619: C12H22O11+H2OAC6H12O6(B)+C6H12O6(C)
C6H12O6D2C2H5OH+2CO2 a) Identify A,B,C and D in the given
chemical reactions. b) What is wash? c) How is rectified spirit obtained
from wash? d) What is the purpose of denaturing rectified spirit?
Answer: a) A = Invertase (enzyme)27; B = Glucose27; C = Fructose27; D =
Zymase (enzyme)27. b) Wash is the 8%–10% ethanol solution obtained after
the fermentation of molasses27. c) Rectified spirit (95.6% ethanol) is
obtained when wash is subjected to fractional distillation28. d)
Denaturing rectified spirit involves adding toxic substances (like
methanol or pyridine) to ethanol to prevent its misuse as a beverage28.
Question 720: a) How is ethanoic acid prepared industrially? b) 5%–8% ethanoic acid is called ...................
Answer: a) Ethanoic acid is prepared industrially by treating methanol
(CH3OH) with carbon monoxide (CO) in the presence of a catalyst29. b)
5%–8% ethanoic acid is called vinegar30.
Question 820: CH3–COOH+CH3–OHconc. H2SO4CH3–COO–CH3+H2O a) What
is the name of this chemical reaction? b) What is the name of the ester
formed? c) Write any two uses of esters.
Answer: a) Esterification30. b) The ester formed is Methyl ethanoate
(from ethanoic acid and methanol)3132. c) Esters are used to make
artificial perfumes and juices because they possess the fragrance of
flowers and fruits31.
Unit 3: Periodic Table and Electron Configuration
I. Let us assess33...
Question 133: The element X having 3 shells belongs to group 17. a)
Write the subshell electron configuration of this element. b) To which
block does this element belong? c) What is its period number? d) Write
the molecular formula of the compound formed when X reacts with an atom
of element Y which belongs to the third period and has one electron in
its p subshell.
Answer: a) Element X is in period 3 (3 shells)37 and group 17
(p-block)38. It must have 7 outermost electrons (2 in s and 5 in p
subshells)39. Subshell electron configuration: 1s22s22p63s23p5. (Cl) b)
p-block (since the last electron is added to the p subshell)40. c) 3
(The highest shell number is 3)41. d) Element Y is in period 3 and has 1
electron in its p subshell. Outermost configuration: 3s23p1. This
element is in Group 13 (2 + 10 + 1 = 13)39. (Aluminium, Al). Element X
(Cl) has oxidation state −1. Element Y (Al) has oxidation state +3.
Molecular formula: \text{Y}\text{X}_3 (e.g., AlCl3).
Question 23334: A few subshells are given. 3p,4d,3f,2d,2p. a) Among
these, which subshells are not possible? b) Explain the reason.
Answer: a) The subshells that are not possible are \text{3f} and
\text{2d}42. b) The Azimuthal quantum number (l) defines subshells and
its value ranges from 0 to (n−1)43.
• For 3f: n=3. The maximum possible value for l is (3−1)=2 (representing
s,p,d). Since l=3 corresponds to the f subshell, 3f is not
possible4243.
• For 2d: n=2. The maximum possible value for l is (2−1)=1 (representing
s,p). Since l=2 corresponds to the d subshell, 2d is not possible4243.
Question 735: Which subshell is represented by each pair of the quantum number values given below? a) n=1,l=0 b) n=2,l=1
Answer: a) n=1,l=0: 1\text{s} subshell (where l=0 denotes the s
subshell)4244. b) n=2,l=1: 2\text{p} subshell (where l=1 denotes the p
subshell)4244.
Question 103645: Iron (Fe) takes part in chemical reactions and becomes
Fe3+ ion. (Atomic number of Fe=26). a) Write the electron configuration
of this ion. b) Write the chemical formula of the compound formed when
this ion combines with sulphate ion (SO42−). c) Which is the other
oxidation state of this element? Write the electron configuration of the
ion thus formed. d) Iron shows variable oxidation states. Why?
Answer: a) Neutral Fe configuration: 1s22s22p63s23p63d64s246. To form
Fe3+, three electrons are lost: two from the outermost 4s subshell and
one from the 3d subshell46. Fe3+ electron configuration: 1\text{s}^2
2\text{s}^2 2\text{p}^6 3\text{s}^2 3\text{p}^6 3\text{d}^546. b) The
Fe3+ ion combines with SO42− ion. Chemical formula:
\text{Fe}_2(\text{SO}_4)_3. c) The other common oxidation state is +2
(Ferrous)47. The ion formed is Fe2+ (loses two 4s electrons)46. Electron
configuration of Fe2+: 1\text{s}^2 2\text{s}^2 2\text{p}^6 3\text{s}^2
3\text{p}^6 3\text{d}^648. d) Iron (a transition element) shows variable
oxidation states because there is only a slight energy difference
between the outermost \text{s} subshell and the penultimate \text{d}
subshell. As a result, electrons from the d subshell can also
participate in chemical reactions under favourable conditions49.
Unit 4: Gas Laws and Mole Concept
I. Activity: Calculation of Volume using Combined Gas Equation50
Question: The volume of a gas at 27∘C and 1 atm pressure is 100 mL. What
will be its volume at 273 K temperature and 2 atm pressure?
Answer: Initial conditions: T1=27∘C=(27+273) K=300 K; P1=1 atm;
V1=100 mL5051. Final conditions: T2=273 K; P2=2 atm; V2=?50. Using
the Combined Gas Equation: T1P1V1=T2P2V250. 3001×100=2732×V2
V2=300×2100×273=6273=45.5 mL50. Volume at 273 K and 2 atm: 45.5\text{
mL}.
II. Let us assess5253
Question 252: Complete the table. (Atomic Mass - H=1,C=12,O=16,N=14).
Substance
Molar Mass (g)
Given mass (g)
Number of moles
Volume at STP (L)
H2
2
10
5
112
CO2
44
440
10
224
NH3
17
340
20
448
(Derivations based on Number of moles = Given mass / Molar mass, and Volume at STP = Number of moles \times 22.4\text{ L})5455:
• H2: Molar Mass = 2×1=2. Moles = 112/22.4=5. Given Mass = 5×2=10.
• CO2: Molar Mass = 12+2(16)=44. Moles = 440/44=10. Volume = 10×22.4=224.
• NH3: Molar Mass = 14+3(1)=17. Moles = 340/17=20. Volume = 20×22.4=448.
Question 553: 400 L of gas is stored in a cylinder at 27∘C and constant
pressure. a) What will be the temperature if the volume of this gas is
reduced to 200 L at the same pressure? b) Which gas law is relevant to
this context? c) The boiling point of a substance is 3∘C. Above what
temperature in Kelvin does this substance obey the gas laws?
Answer: a) This is governed by Charles’s Law (constant pressure)56.
T1=27∘C=300 K51; V1=400 L. T2=?; V2=200 L. T1V1=T2V257.
300400=T2200 T2=400200×300=150 K57. b) Charles’s Law (At constant
pressure, volume is directly proportional to temperature in Kelvin)56.
c) Gas laws describe the properties of gases51. Since the boiling point
is 3∘C, the substance must be in the gaseous state above this
temperature. 3∘C=(3+273) K=276 K. The substance obeys the gas laws above
276\text{ K}51.
Unit 5: Electrochemistry
I. Conceptual Questions
Question: Why can silver nitrate solution not be stored in a copper
vessel?58 Answer: Copper is a more reactive metal than silver5960. The
more reactive metal (Copper) will displace the less reactive metal (Ag+
ion) from its salt solution58. The reaction is
Cu+2AgNO3→Cu(NO3)2+2Ag60, meaning the copper vessel would dissolve60.
Question: Which of the following metals can displace hydrogen from
hydrochloric acid? (Sodium, gold, silver, aluminium)61 Answer: Sodium
and Aluminium. The metals placed above hydrogen in the reactivity series
can displace hydrogen from dilute acids61.
Question: Define fuel cells and write its advantage.62 Answer: Fuel
cells are galvanic cells designed to convert the chemical energy
produced by the combustion of fuels (such as hydrogen, methane, and
methanol) directly into electrical energy63. An advantage is that they
produce electricity with high efficiency63.
II. Let us assess62...
Question 164: Examine the diagram of a galvanic cell (Zn/Cu) and find
out whether the given statements are true or false. a) As the cell
operates, the mass of the zinc rod, Zn(s) decreases. b) The copper
electrode is the anode. c) Electrons flow from the zinc electrode to the
copper electrode through the external circuit. d) During cell reaction,
reduction takes place at the copper electrode. e) During cell reaction,
the concentration of Cu2+ decreases.
Answer: a) True (Oxidation occurs: Zn(s)→Zn2+(aq)+2e−)66. b) False (Zinc
is the anode (oxidation), Copper is the cathode (reduction))66. c) True
(Flow is from anode (Zn) to cathode (Cu))67. d) True (Reduction occurs
at the cathode: Cu2+(aq)+2e−→Cu(s))66. e) True (Cu2+ ions are consumed
to form Cu metal at the cathode)68.
Question 465: When an aqueous sodium chloride solution is electrolysed,
the reaction that takes place at the anode is: (i) Na+(aq)+e−→Na(s) (ii)
2H2O(l)→4H+(aq)+O2(g)+4e− (iii) H+(aq)+e−→21H2(g) (iv)
Cl−(aq)→21Cl2(g)+e−
Answer: (iv) \text{Cl}^{-}(\text{aq}) \to
\frac{1}{2}\text{Cl}_2(\text{g}) + \text{e}^{-} (Chloride ions are
oxidised to chlorine gas at the anode)6970.
Question 565: Write the products obtained when the following solutions
undergo electrolysis. (i) Aqueous solution of NaCl (ii) Aqueous solution
of CuSO4 (using copper electrodes)
Answer: (i) Products: \text{H}_2 gas (at cathode), \text{Cl}_2 gas (at
anode), and an aqueous solution of \text{NaOH}7071. (ii) The process is
electrolytic refining. Products: The impure copper anode dissolves
(Cu→Cu2+), and pure copper is deposited on the cathode (Cu2+→Cu)7273.
Question 662: Brass is an alloy of zinc and copper. When brass comes
into contact with saline water, corrosion of metal takes place and zinc
gradually dissolves in the solution, leaving copper behind. Explain why
zinc dissolves in comparison to copper.
Answer: Zinc is more reactive than copper; this is indicated by its
higher position in the reactivity series59. When two metals are in
contact in the presence of an electrolyte (like saline water), the more
reactive metal acts as the anode and is destroyed (corrodes), thus
protecting the less reactive metal (copper)7475.
Unit 6: Metals
I. Conceptual Questions
Question: What are the qualities of a mineral which is used to extract a
metal?76 Answer: The mineral should have: Abundance, Ease of
extraction, High metal content, and Low production cost7677.
Question: The nature of ores is given. Complete the table using appropriate concentration methods.7879
Nature of ore
Concentration method
Froth floatation8081
2. Ores have magnetic properties but impurities are non magnetic.
Magnetic separation7981
3. A solvent which dissolves the ore is used.
Leaching7881
4. Ores are denser than the impurities.
Levigation (Hydraulic washing)80
Question: What type of flux should be used if the gangue in the ore is
basic in nature?82 Answer: An acidic flux should be used, as the flux
combines with the gangue to form molten slag8283.
II. Let us assess84...
Question 184: Define the following and answer the given questions. (1)
Ore - What is the ore of aluminium? (2) Roasting - Which type of ores
are subjected to roasting? (3) Reducing agent - What is the reducing
agent used in the manufacture of aluminium? (4) Flux - Which flux is
used in the manufacture of copper? Why? (5) Leaching - Which metal ore
is leached with sodium cyanide?
Answer: (1) Ore: Any mineral from which a metal can be extracted easily
and economically77. Ore of aluminium: Bauxite (Al2O3⋅2H2O)77. (2)
Roasting: Heating the concentrated ore at a temperature below the
melting point in the presence of air88. Ores subjected to roasting:
Sulphide ores8188. (3) Reducing agent for aluminium: Electricity (or
e−)8589. (4) Flux used in copper manufacture: Sand (\text{SiO}_2)90.
This is an acidic flux, and it is used because the ore contains basic
impurities (such as iron oxide)9091. (5) Metal ores leached with sodium
cyanide (NaCN): Gold and Silver ores78.
Question 284: Find the relation and write the answer. Zinc sulphide :
Roasting Calcium carbonate : .................... Magnetite : Magnetic
separation Bauxite : ....................
Answer:
• Zinc sulphide : Roasting Calcium carbonate : Calcination88.
• Magnetite : Magnetic separation Bauxite : Leaching78.
Question 485: Following are two facts related to the manufacture of an
industrially important metal. y The ore is treated with hot NaOH
solution. y Electricity is used as the reducing agent to extract the
metal. (i) These facts are related to the production of which metal?
(ii) What is the reason for using electricity as the reducing agent?
(iii) Which substance is used as the electrolyte here? (iv) Which gas is
liberated at the anode?
Answer: (i) The metal is Aluminium92. (ii) Aluminium is a highly
reactive metal (and forms stable compounds)93. Strong reducing agents
(like electrolysis) are required to extract highly reactive metals8589.
(iii) The electrolyte is anhydrous Alumina (Al2O3) dissolved in molten
Cryolite (Na3AlF6)94. (iv) Oxygen gas (O2) is liberated at the
anode95.
Question 686: Corrosion is a process by which iron is converted into its
oxide. This is an oxidation reaction. (i) What is oxidation? (ii)
Complete the following chemical equation. ....... Fe+ ....... O2→
....... Fe2O3 (iii) Suggest two methods for preventing the corrosion
of iron.
Answer: (i) Corrosion (as an oxidation process): A process in which the
metal reacts with its surrounding medium and undergoes chemical
change8696. (ii) 4Fe+3O2→2Fe2O386. (iii) Two methods:
Electroplating9798 and Cathodic protection (e.g., attaching zinc or
magnesium blocks to iron)75.
Question 787: Alloys containing iron are given. Find a,b,c,d.
Alloys
Constituent elements
Uses
Alnico
(a) Fe, Al, Ni, Co99
(b) Making of permanent magnets99
Stainless steel
(c) Fe, Cr, Ni, C100
Resist the corrosion of iron. Making of utensils
Silicon steel
Fe, Si, C
(d) Used in the core of electromagnetic instruments (e.g., motors, generators, transformers) as it reduces electric loss100
Unit 7: Some Compounds of Industrial Importance
I. Conceptual Questions
Question: Why is the jar used for collecting ammonia kept inverted?101
Answer: Ammonia gas is less dense than atmospheric air101.
Question: Why does the water entering the flask change its colour (to
pink) in the ammonia fountain experiment?102103 Answer: Ammonia
dissolves in water to form ammonium hydroxide (NH4OH), which is an
alkaline substance (base)103104. Phenolphthalein is an indicator that
gives a pink colour with alkaline substances103.
Question: Concentrated H2SO4 is not used as a drying agent in the
preparation of NH3. Why?105 Answer: Concentrated H2SO4 and NH3 react
chemically105.
Question: What are the essential qualities of fertilizers?106107 Answer:
Electrode
Reaction Type
Chemical Equation
Product(s) Formed
Left
Anode (+)
Oxidation119
2Cl−→Cl2+2e−119
Chlorine gas (\text{Cl}_2)119
Right
Cathode (–)
Reduction120
2H2O+2e−→H2+2OH−120
Hydrogen gas (\text{H}_2) and Sodium Hydroxide (\text{NaOH})120
Question 6110: Explain the effect of pressure on the following
reversible reactions. (i) H2(g)+I2(g)⇌2HI(g) (ii)
N2(g)+3H2(g)⇌2NH3(g)
Answer: Pressure affects equilibrium only if the number of gaseous
molecules changes in the reaction121. (i) No effect: Total moles of
reactants (H2+I2) is 2; total moles of product (2HI) is 2. Since the
number of moles of gaseous molecules does not change, pressure will have
no effect on the chemical equilibrium121122. (ii) Pressure increases
product yield: Total moles of reactants (N2+3H2) is 4; total moles of
product (2NH3) is 2. According to Le Chatelier’s principle, increasing
pressure shifts the equilibrium in the direction where the number of
moles decreases123. Thus, increasing pressure favors the forward
reaction, increasing the production of NH3124.
Question 7110: 2NO(g)+O2(g)⇌2NO2(g)+heat (Forward reaction is
exothermic, 3 moles→2 moles). Complete the table by indicating the
possible measures to increase the amount of NO2 (product).
Answer:
Change Applied
Effect on NO2 Production
Reason (Le Chatelier’s Principle)
Temperature
Decrease110
Favours the exothermic reaction (forward reaction)125.
Pressure
Increase110
Favours the direction with fewer moles (forward reaction, 3 → 2)123124.
Amount of oxygen
Increase110
Increases reactant concentration, shifts equilibrium forward126127.
Amount of NO
Increase110
Increases reactant concentration, shifts equilibrium forward126127.
Question 11112: (i) Which substance is used as the drying agent in the
laboratory preparation of ammonia? (ii) Can concentrated sulphuric acid
be used as a drying agent in this process? Write the chemical equation
that occurs if it is used.
Answer: (i) The drying agent used is Quick lime (\text{CaO})101. (ii)
Concentrated sulphuric acid cannot be used105. This is because ammonia
(NH3) reacts with concentrated sulphuric acid (H2SO4)105. The
chemical equation (implied reaction): 2NH3+H2SO4→(NH4)2SO4112.
Question 12113: Complete the table.
Function in plants
Fertilizers that can be used
To accelerate plant growth.
Urea, sodium nitrate (Nitrogenous fertilizers)128
To increase productivity.
Ammonium phosphate, potassium chloride (Phosphate and Potash fertilizers)128
To boost immunity of plants.
Potassium chloride (Potash fertilizers)128write without page reference numbers
Unit 1: Nomenclature of Organic Compounds and Isomerism
Organic chemistry is a specific branch of chemistry dedicated to the study of carbon compounds, which are often formed when carbon combines with elements such as hydrogen, oxygen, and nitrogen.
Nomenclature of Alkanes with Branches
Nomenclature of Unsaturated Hydrocarbons
Unsaturated hydrocarbons contain double (alkenes) or triple (alkynes)
bonds. The position of the double or triple bond must receive the lowest
position number during chain numbering.
Functional Groups
A functional group is an atom or a group of atoms bonded to carbon in an
organic compound that determines the distinctive chemical and physical
properties of that compound.
| Functional Group | Name of Group | Common Name | IUPAC Naming Rule | Example |
|---|---|---|---|---|
| −OH | Hydroxyl | Alcohol | Alkane - 'e' + 'ol' (Alkanol) | Methanol (CH₃−OH) |
| −COOH | Carboxyl | Carboxylic acid | Alkane - 'e' + 'oic acid' (Alkanoic acid) | Ethanoic acid (CH₃COOH) |
| −CHO | Aldehydic | Aldehyde | Alkane - 'e' + 'al' (Alkanal) | Ethanal (CH₃CHO) |
| C=O | Keto | Ketone | Alkane - 'e' + 'one' (Alkanone) | Propanone (H₃CCOCH₃) |
| −F,−Cl,−Br,−I | Halo | Halo compounds | Position of halo group + name of halo group + name of alkane | 1–Chloropropane |
| −O−R | Alkoxy | Ether | Alkoxyalkane (Shorter alkyl group is 'alkoxy', longer is 'alkane') | Methoxyethane |
Isomerism
Isomers are compounds that have the same molecular formula but different
structural formulae, leading to different chemical and physical
properties. The phenomenon is isomerism.
Unit 2: Chemical Reactions of Organic Compounds
Major organic reactions include substitution, addition, combustion, thermal cracking, and polymerisation.
Types of Chemical Reactions
| Reaction Type | Description | Example/Notes |
|---|---|---|
| Substitution | An atom or group of atoms is replaced with another atom or group of atoms in a compound. | CH₄ + Cl₂ --(sunlight)--> CH₃Cl + HCl. |
| Addition | Unsaturated organic compounds (double or triple bonds) combine with certain molecules to form saturated compounds. | CH₂=CH₂ + H₂ --(Ni)--> CH₃−CH₃. |
| Polymerisation | Simple molecules (monomers) join together to form large complex molecules (polymers). | Ethene (monomer) → polyethene (polymer). |
| Addition Polymerisation | Polymers obtained by repeated addition reaction of monomers (e.g., Polythene, PVC, Teflon). | nCH₂=CH₂ → [CH₂−CH₂]ₙ. |
| Condensation Polymerisation | Different monomers combine with the removal of simple molecules (e.g., H₂O) (e.g., Nylon 66, Bakelite). | Nylon 66 monomers: adipic acid and hexamethylenediamine. |
| Thermal Cracking | Hydrocarbons with high molecular weight are heated in the absence of air and decompose into hydrocarbons with lower molecular weight (saturated and unsaturated). | CH₃−CH₂−CH₃ --(heat)--> CH₄ + CH₂=CH₂. |
| Combustion | Hydrocarbons burn, combining with oxygen to form CO₂ and H₂O along with heat and light. | CH₄ + 2O₂ → CO₂ + 2H₂O + Heat. |
Important Organic Compounds
Unit 3: Periodic Table and Electron Configuration
Atomic Model and Orbitals
The quantum mechanical model of the atom superseded the Bohr model
limitations (due to the wave nature of matter and Heisenberg’s
Uncertainty Principle).
Electron Accommodation
Subshell Electron Configuration
Subshell electron configuration is the arrangement where electrons fill
gradually in the subshells in the increasing order of energy.
Finding Element Position
Periodic Trends (Ionisation Enthalpy)
Ionisation enthalpy is the minimum energy required to remove the most
loosely bound electron from the outermost shell of an isolated gaseous
atom.
Characteristics of Elements by Block
| Block | Groups | Key Characteristics |
|---|---|---|
| s-block | 1 and 2 | Low ionisation enthalpy. Exhibit fixed oxidation states (+1 or +2). Valence configuration ns¹ or ns². |
| p-block | 13 to 18 | Includes metals, nonmetals, and metalloids. Exhibit both positive (+) and negative (−) oxidation states. |
| d-block | 3 to 12 | Transition elements. All are metals. Show similarities in properties along periods due to similar outermost subshell configuration (ns¹⁻²). Show variable oxidation states because the energy difference between the outermost s subshell and the penultimate d subshell is slight, allowing d electrons to participate in reactions. Compounds are generally coloured. |
| f-block | (Inner Transition) | Electrons are filled in the anti penultimate shell. Show variable oxidation states. Actinoids are radioactive. Used as nuclear fuels and for strong magnets. |
Unit 4: Gas Laws and Mole Concept
Properties of Gases (Kinetic Molecular Theory)
Gases are composed of minute particles (atoms/molecules). They exhibit:
Gas Laws
| Law | Relation | Condition | Equation | Notes |
|---|---|---|---|---|
| Boyle’s Law | Volume (V) is inversely proportional to Pressure (P). | Constant Temperature, Fixed Mass | P₁V₁ = P₂V₂ = k | Increasing pressure decreases volume. |
| Charles’s Law | Volume (V) is directly proportional to Temperature (T in K). | Constant Pressure, Fixed Mass | V₁/T₁ = V₂/T₂ = k | Temperature must be in Kelvin (K). Absolute Zero is 0 K or −273.15°C. |
| Avogadro’s Law | Volume (V) is directly proportional to the number of molecules (N). | Constant Temperature and Pressure | V ∝ N | Equal volumes of all gases contain an equal number of molecules. |
| Combined Gas Eq. | Combines Boyle's and Charles's laws. | Fixed Mass | P₁V₁/T₁ = P₂V₂/T₂ | |
| Ideal Gas Eq. | Combines all three laws. | PV = nRT | R is the Universal Gas Constant. |
Mole Concept
Unit 5: Electrochemistry
Electrochemistry is the branch of chemistry that deals with processes producing electricity through chemical reactions and using electricity to bring about chemical reactions.
Electrochemical Cells
Electrochemical cells enable these changes. They are divided into Galvanic cells and Electrolytic cells.
Reactivity Series
The series in which elements are arranged in the decreasing order of their tendency to get oxidised (reactivity).
Electroplating
Electroplating is the process of coating a layer of one metal onto
another metal through electrolysis to enhance beauty and prevent
corrosion.
Types of Electrochemical Cells (Energy Sources)
Unit 6: Metals
Minerals and Metallurgy
1. Concentration of Ores (Removing Gangue)
| Method | Principle | Application |
|---|---|---|
| Levigation (Hydraulic washing) | Separates ores denser than gangue by washing in a water stream. | Generally for oxide ores. |
| Froth Floatation | Separates ores less dense than gangue; ore particles stick to froth formed using pine oil and water. | Generally for sulphide ores. |
| Magnetic Separation | Separates magnetic components (either ore or gangue) using a magnetic roller. | Magnetite (Fe₃O₄), Tinstone (SnO₂). |
| Leaching | Powdered ore dissolves in a suitable solvent; gangue remains insoluble. | Bauxite, Gold, Silver ores. |
2. Extraction of Metal
The method depends on the metal's reactivity.
Iron Extraction
Aluminium Extraction (Hall-Heroult Process)
3. Refining of Metals
Refining removes impurities to produce pure metal.
Corrosion and Prevention
Corrosion is a process where a metal reacts with its surrounding medium and undergoes chemical change.
Unit 7: Some Compounds of Industrial Importance
Ammonia (NH₃)
Ammonia is crucial for producing nitrogenous fertilizers.
Chemical Equilibrium and Le Chatelier’s Principle
A reaction is reversible if it proceeds in both the forward and backward directions simultaneously (NH₃ + HCl ⇌ NH₄Cl).
Chemical equilibrium is the stage where the rate of the forward reaction
equals the rate of the backward reaction in a reversible reaction. It
is a dynamic equilibrium at the molecular level and is possible only in a
closed system.
Le Chatelier’s Principle: When concentration, pressure,
or temperature of a system at equilibrium is changed, the system will
readjust itself to nullify the effect of that change.
| Change Applied | Effect on Equilibrium Shift |
|---|---|
| Increase Reactant Conc. | Shifts to increase rate of forward reaction (consumes reactants). |
| Increase Product Conc. | Shifts to increase rate of backward reaction (consumes products). |
| Increase Pressure (Gases) | Shifts in the direction where the number of moles of molecules decreases. (No effect if number of moles is equal, e.g., H₂ + I₂ ⇌ 2HI). |
| Increase Temperature | Shifts to increase rate of the endothermic reaction. |
| Catalyst Addition | Increases rate of both forward and backward reactions equally, allowing equilibrium to be reached faster, but does not affect the equilibrium state itself. |
Sulphuric Acid (H₂SO₄)
Sulphuric acid is called the ‘King of Chemicals’ due to its industrial importance.
Basicity of Acids and Alkalies
Sodium Hydroxide (NaOH) and Hydrochloric Acid (HCl)
Salts and Hydrolysis
Salts are formed from acid-base neutralisation reactions.
| Salt Type | Formation Basis | Solution Nature | Example |
|---|---|---|---|
| Neutral Salt | Strong Acid + Strong Base | Neutral (No hydrolysis) | NaCl |
| Acid Salt | Strong Acid + Weak Base | Acidic (Undergoes hydrolysis) | NH₄Cl |
| Basic Salt | Weak Acid + Strong Base | Basic (Undergoes hydrolysis) | Na₂CO₃ |
Salt hydrolysis is the process where ions of a salt react with water to form a solution that is acidic or basic.
Fertilizers
Fertilizers supply necessary nutrients for plant growth.
| Fertilizer Type | Effect on Plants | Examples |
|---|---|---|
| Nitrogenous | Accelerates growth. | Urea, Ammonium sulphate. |
| Phosphate | Helps growth, increases productivity. | Ammonium phosphate. |
| Potash | Helps growth, increases productivity, boosts immunity. | Potassium chloride. |
Unit 1: Nomenclature of Organic Compounds and Isomerism
Organic chemistry is a specific branch of chemistry dedicated to the
study of carbon compounds, which are often formed when carbon combines
with elements such as hydrogen, oxygen, and nitrogen3.
Nomenclature of Alkanes with Branches
Name of Group
Common Name
IUPAC Naming Rule
Example
−OH
Hydroxyl
Alcohol
Alkane - 'e' + 'ol' (Alkanol)1920
Methanol (CH3−OH)20
−COOH
Carboxyl
Carboxylic acid
Alkane - 'e' + 'oic acid' (Alkanoic acid)21
Ethanoic acid (CH3COOH)22
−CHO
Aldehydic
Aldehyde
Alkane - 'e' + 'al' (Alkanal)23
Ethanal (CH3CHO)24
C=O
Keto
Ketone
Alkane - 'e' + 'one' (Alkanone)2526
Propanone (H3CCOCH3)26
−F,−Cl,−Br,−I
Halo
Halo compounds
Position of halo group + name of halo group + name of alkane27
1–Chloropropane27
−O−R
Alkoxy
Ether
Alkoxyalkane (Shorter alkyl group is 'alkoxy', longer is 'alkane')28
Methoxyethane28
Isomerism
Isomers are compounds that have the same molecular formula but different
structural formulae, leading to different chemical and physical
properties. The phenomenon is isomerism29.
Unit 2: Chemical Reactions of Organic Compounds
Major organic reactions include substitution, addition, combustion, thermal cracking, and polymerisation37.
Types of Chemical Reactions
Reaction Type
Description
Example/Notes
Substitution
An atom or group of atoms is replaced with another atom or group of atoms in a compound38.
CH4+Cl2sunlightCH3Cl+HCl38.
Addition
Unsaturated organic compounds (double or triple bonds) combine with certain molecules to form saturated compounds39.
CH2=CH2+H2NiCH3−CH340.
Polymerisation
Simple molecules (monomers) join together to form large complex molecules (polymers)41.
Ethene (monomer) → polyethene (polymer)42.
Addition Polymerisation
Polymers obtained by repeated addition reaction of monomers (e.g., Polythene, PVC, Teflon)4243.
nCH2=CH2→[CH2−CH2]n42.
Condensation Polymerisation
Different monomers combine with the removal of simple molecules (e.g., H2O) (e.g., Nylon 66, Bakelite)4445.
Nylon 66 monomers: adipic acid and hexamethylenediamine44.
Thermal Cracking
Hydrocarbons with high molecular weight are heated in the absence of air and decompose into hydrocarbons with lower molecular weight (saturated and unsaturated)4647.
CH3−CH2−CH3heatCH4+CH2=CH246.
Combustion
Hydrocarbons burn, combining with oxygen to form \text{CO}_2 and \text{H}_2\text{O} along with heat and light48.
CH4+2O2→CO2+2H2O+Heat49.
Important Organic Compounds
• Methanol (\text{CH}_3-\text{OH}): Also called wood spirit50.
Industrially produced by treating carbon monoxide (CO) with hydrogen
(H2) in the presence of catalysts5051. It is a poisonous substance51.
• Ethanol (\text{CH}_3-\text{CH}_2-\text{OH}): Industrially manufactured
by the fermentation of molasses using invertase and zymase enzymes5152.
◦ 8%−10% ethanol is 'wash'52.
◦ 95.6% ethanol obtained by fractional distillation is rectified spirit53.
◦ 100% ethanol is absolute alcohol53.
◦ Denatured spirit is ethanol mixed with toxic substances (like methanol or pyridine) to prevent its misuse as a beverage5354.
• Ethanoic Acid (\text{CH}_3-\text{COOH}): Industrially prepared by
treating methanol with carbon monoxide in the presence of a catalyst55.
◦ 5%−8% ethanoic acid, produced by fermentation of ethanol with acetobacter bacteria, is called vinegar56.
• Esters: Formed when alcohols react with carboxylic acids. This reaction is called esterification5657.
◦ General formula: R−COO−R156.
◦ Used to make artificial perfumes and juices because they possess the fragrance of flowers and fruits57.
Unit 3: Periodic Table and Electron Configuration
Atomic Model and Orbitals
The quantum mechanical model of the atom superseded the Bohr model
limitations (due to the wave nature of matter and Heisenberg’s
Uncertainty Principle)5859.
• Orbitals: Regions around the nucleus where there is maximum probability of finding the electrons59.
• Quantum Numbers: Used to describe orbitals and electrons59.
◦ Principal Quantum Number (n): Represents shells (principal energy levels, K, L, M, N). Values are 1,2,3,4,…60.
◦ Azimuthal Quantum Number (l): Represents subshells (s,p,d,f) and
defines the 3D shape of the orbital60. Values range from 0 to (n−1)60.
◦ Magnetic Quantum Number (m): Represents the difference in orientation
of orbitals61. For a value l, there are (2l+1) values for m61.
▪ s subshell (l=0): 1 orbital (spherical shape)62.
▪ p subshell (l=1): 3 orbitals (dumbbell shape)62.
▪ d subshell (l=2): 5 orbitals6263.
▪ f subshell (l=3): 7 orbitals63.
Electron Accommodation
• The total number of orbitals in each shell is n263.
• The maximum number of electrons that can be accommodated in each shell is 2n264.
• The maximum number of electrons that can be accommodated in each orbital is 265.
• Maximum electrons per subshell: s-2, p-6, d-10, f-1466.
Subshell Electron Configuration
Subshell electron configuration is the arrangement where electrons fill
gradually in the subshells in the increasing order of energy67.
• Energy Order: Determined by the (n+l) values. The subshell with a
higher (n+l) value has more energy68. If (n+l) values are equal, the
subshell with the higher n value has more energy (e.g., 3s > 2p)69.
• The energy of subshells increases in the order: 1s<2s<2p<3s<3p<4s<3d<… (e.g., 4s fills before 3d)70.
• Stability Anomaly (\text{Cr} and \text{Cu}): Configurations with
half-filled (d5) or completely filled (d10) d subshells are more
stable71. To achieve this stability, electrons shift, so d4s2 becomes
d5s1 (Chromium) and d9s2 becomes d10s1 (Copper)7172.
Finding Element Position
• Block: The block to which an element belongs is the same as the subshell to which the last electron was added73.
• Period Number: The period number is the highest shell number in its subshell electron configuration7475.
• Group Number:
◦ s-block (Groups 1, 2): Number of electrons in the outermost s subshell76.
◦ p-block (Groups 13–18): 10 + (Total number of electrons in the outermost s and p subshells)77.
◦ d-block (Groups 3–12): Sum of the number of electrons in the outermost
s subshell and the number of electrons in the d subshell preceding
it78.
Periodic Trends (Ionisation Enthalpy)
Ionisation enthalpy is the minimum energy required to remove the most
loosely bound electron from the outermost shell of an isolated gaseous
atom79.
• Down a Group: Ionisation enthalpy decreases. The increasing number of
shells increases the distance of the outermost electron from the
nucleus, weakening the attractive force80.
• Across a Period (L to R): Ionisation enthalpy increases. The nuclear
charge gradually increases with no change in the number of shells,
leading to a stronger attractive force on the outermost electrons81.
Characteristics of Elements by Block
Block
Groups
Key Characteristics
s-block
1 and 2
Low ionisation enthalpy82. Exhibit fixed oxidation states (+1 or +2)83. Valence configuration ns1 or ns284.
p-block
13 to 18
Includes metals, nonmetals, and metalloids85. Exhibit both positive (+) and negative (−) oxidation states86.
d-block
3 to 12
Transition elements86. All are metals86. Show similarities in
properties along periods due to similar outermost subshell configuration
(ns1−2)87. Show variable oxidation states because the energy difference
between the outermost s subshell and the penultimate d subshell is
slight, allowing d electrons to participate in reactions88. Compounds
are generally coloured89.
f-block
(Inner Transition)
Electrons are filled in the anti penultimate shell90. Show variable oxidation states. Actinoids are radioactive91. Used as nuclear fuels and for strong magnets92.
Unit 4: Gas Laws and Mole Concept
Properties of Gases (Kinetic Molecular Theory)
Gases are composed of minute particles (atoms/molecules)93. They exhibit:
• Very high distance between molecules, leading to negligible attractive force9394.
• Molecules are in constant random motion; collisions with the container walls result in gaseous pressure95.
• Collisions are elastic (kinetic energy before and after collision is the same)95.
• The average kinetic energy of molecules is directly proportional to its temperature95.
• The volume of a gas is the volume of the container in which it is occupied96.
Gas Laws
Law
Relation
Condition
Equation
Notes
Boyle’s Law
Volume (V) is inversely proportional to Pressure (P)97.
Constant Temperature, Fixed Mass97
P1V1=P2V2=k98
Increasing pressure decreases volume97.
Charles’s Law
Volume (V) is directly proportional to Temperature (T in K)99.
Constant Pressure, Fixed Mass99
V1/T1=V2/T2=k100
Temperature must be in Kelvin (K)99. Absolute Zero is 0 K or −273.15∘C101.
Avogadro’s Law
Volume (V) is directly proportional to the number of molecules (N)102.
Constant Temperature and Pressure102
VαN102
Equal volumes of all gases contain an equal number of molecules102.
Combined Gas Eq.
Combines Boyle's and Charles's laws103.
Fixed Mass
P1V1/T1=P2V2/T2104
Ideal Gas Eq.
Combines all three laws105.
PV=nRT105
R is the Universal Gas Constant105.
Mole Concept
• Mole: The quantity of a substance containing 6.022 \times 10^{23} particles (atoms/molecules/ions)106107.
• Avogadro Number (\text{N}_{\text{A}}): The number 6.022×1023107. Mole is the SI unit of quantity of matter107.
• Gram Atomic Mass (GAM): The mass of an element equal to its relative atomic mass in grams. Contains 1 mole of atoms108.
• Molar Mass (Gram Molecular Mass): The molecular mass of a compound expressed in grams. Contains 1 mole of molecules109110.
• Calculating Moles: Number of moles = Given mass / Molar mass111.
• Standard Temperature and Pressure (STP): Fixed at 273 K and 1 atm pressure112.
• Molar Volume at STP: At STP, one mole of any gas occupies a volume of 22.4 L112.
◦ Number of moles of gases at STP = Given volume (L) / 22.4 L112.
• Stoichiometry: In a balanced chemical equation, the coefficients
represent the ratios of moles of reactants and products. This allows the
determination of required amounts of substances113....
Unit 5: Electrochemistry
Electrochemistry is the branch of chemistry that deals with processes
producing electricity through chemical reactions and using electricity
to bring about chemical reactions116.
Electrochemical Cells
Electrochemical cells enable these changes. They are divided into Galvanic cells and Electrolytic cells117.
Reaction/Property
Charge Representation
Anode (e.g., Zinc)
Where oxidation occurs (Zn→Zn2++2e−)118.
Negative electrode119.
Cathode (e.g., Copper)
Where reduction occurs (Cu2++2e−→Cu)118.
Positive electrode119.
Electron Flow
From anode (Zn) to cathode (Cu) through the external circuit120.
Salt Bridge
Connects the half cells, ensures electrical contact, and maintains electrical neutrality within the internal circuit121.
Unit 6: Metals
Minerals and Metallurgy
• Mineral: Naturally occurring metal or compound137.
• Ore: Any mineral from which a metal can be extracted easily and
economically. Ores typically have high metal content, are abundant, and
allow ease of extraction at low cost (e.g., Bauxite (Al2O3⋅2H2O) for
Aluminium)137138.
• Metallurgy: The process of metal extraction, involving three stages:
Concentration of ores, Extraction of metal from concentrated ore, and
Refining of metal139.
Principle
Application
Levigation (Hydraulic washing)
Separates ores denser than gangue by washing in a water stream140.
Generally for oxide ores140.
Froth Floatation
Separates ores less dense than gangue; ore particles stick to froth formed using pine oil and water140.
Generally for sulphide ores141.
Magnetic Separation
Separates magnetic components (either ore or gangue) using a magnetic roller141.
Magnetite (Fe3O4), Tinstone (SnO2)141.
Leaching
Powdered ore dissolves in a suitable solvent; gangue remains insoluble141.
Bauxite, Gold, Silver ores142.
2. Extraction of Metal
The method depends on the metal's reactivity143.
Unit 7: Some Compounds of Industrial Importance
Ammonia (NH3)
Ammonia is crucial for producing nitrogenous fertilizers167.
• Laboratory Preparation: Ammonium chloride (NH4Cl) heated with calcium
hydroxide (Ca(OH)2)167. Ammonia gas has a pungent smell and is basic
in nature168. It is highly soluble in water169.
• Industrial Preparation (Haber Process): Nitrogen and hydrogen combine
in a 1:3 ratio at high pressure and temperature170. Sponge iron is used
as the catalyst170. N2(g)+3H2(g)⇌2NH3(g)+heat The reaction is
reversible and exothermic170....
Chemical Equilibrium and Le Chatelier’s Principle
A reaction is reversible if it proceeds in both the forward and backward directions simultaneously (NH3+HCl⇌NH4Cl)171.
Chemical equilibrium is the stage where the rate of the forward reaction
equals the rate of the backward reaction in a reversible reaction173.
It is a dynamic equilibrium at the molecular level and is possible only
in a closed system174.
Le Chatelier’s Principle: When concentration, pressure, or temperature
of a system at equilibrium is changed, the system will readjust itself
to nullify the effect of that change175.
Change Applied
Effect on Equilibrium Shift
Increase Reactant Conc.
Shifts to increase rate of forward reaction (consumes reactants)176.
Increase Product Conc.
Shifts to increase rate of backward reaction (consumes products)176177.
Increase Pressure (Gases)
Shifts in the direction where the number of moles of molecules
decreases178179. (No effect if number of moles is equal, e.g.,
H2+I2⇌2HI)172.
Increase Temperature
Shifts to increase rate of the endothermic reaction172180.
Catalyst Addition
Increases rate of both forward and backward reactions equally,
allowing equilibrium to be reached faster, but does not affect the
equilibrium state itself180.
Sulphuric Acid (H2SO4)
Sulphuric acid is called the ‘King of Chemicals’ due to its industrial importance181.
• Industrial Preparation (Contact Process):
1. Sulphur is converted to sulphur dioxide (SO2)182.
2. SO2 combines with O2 using vanadium pentoxide (\text{V}_2\text{O}_5) as catalyst to form SO3182.
3. SO3 is dissolved in concentrated H2SO4 to produce oleum
(H2S2O7)182. (Direct dissolution of SO3 in water is avoided because
it is highly exothermic and forms a fog/smog)183.
4. Oleum is dissolved in water to produce H2SO4183.
• Properties: Colourless, denser, and higher viscosity than water184.
◦ Dehydrating Agent: Concentrated H2SO4 is a strong dehydrating agent,
absorbing hydrogen and oxygen from substances (like sugar) in the same
ratio as in water (H:O=2:1)185.
◦ Drying Agent: Used to absorb moisture (e.g., in preparation of
CO2,SO2,HCl)186187. (Cannot be used for NH3 as they react)187.
◦ Oxidising Agent: Concentrated H2SO4 reacts with both metals and nonmetals, oxidising them188.
Basicity of Acids and Alkalies
• Basicity of an Acid: The number of H+ ions that the molecule of the
acid can donate189. (Monobasic = 1 H+, Dibasic = 2 H+ (H2SO4),
Tribasic = 3 H+ (H3PO4))189....
• Alkalies (Arrhenius Theory): Substances that liberate OH− ions and
thus increase the concentration of hydroxide ions in aqueous
solutions192.
Sodium Hydroxide (NaOH) and Hydrochloric Acid (HCl)
• Sodium Hydroxide (Caustic Soda): Industrially produced by the
chlor-alkali process193. This involves the electrolysis of concentrated
aqueous sodium chloride solution (brine) using a membrane cell194.
Products are H2 (cathode), Cl2 (anode), and NaOH193.
• Hydrochloric Acid (\text{HCl}): Manufactured by the direct combination of hydrogen and chlorine in an exothermic process195.
Salts and Hydrolysis
Salts are formed from acid-base neutralisation reactions196.
Salt Type
Formation Basis
Solution Nature
Example
Neutral Salt
Strong Acid + Strong Base197
Neutral (No hydrolysis)198
NaCl198
Acid Salt
Strong Acid + Weak Base199
Acidic (Undergoes hydrolysis)197
NH4Cl197
Basic Salt
Weak Acid + Strong Base200
Basic (Undergoes hydrolysis)197
Na2CO3197
Salt hydrolysis is the process where ions of a salt react with water to form a solution that is acidic or basic197.
Fertilizers
Fertilizers supply necessary nutrients for plant growth200.
• Natural Nutrients: Carbon, Hydrogen, Oxygen200.
• Primary Nutrients (needed in large quantities): Nitrogen, Phosphorus, Kalium (Potassium) (NPK)200.
• Secondary Nutrients (needed in small quantities): Calcium, Magnesium, Sulphur200.
• Essential Qualities of Fertilizers: Must be water-soluble, stable
(remain in soil long enough), non-toxic, and should not cause
significant pH variations201202.
Fertilizer Type
Effect on Plants
Examples
Nitrogenous
Accelerates growth203.
Urea, Ammonium sulphate203.
Phosphate
Helps growth, increases productivity203.
Ammonium phosphate203.
Potash
Helps growth, increases productivity, boosts immunity203.
Potassium chloride203.write without page reference numbers
PHYSICS: X Standard
Part 1
Chapter 1: Sound Waves
Oscillations and Wave Characteristics
Vibration Phenomena
Wave Motion and Types
Wave Characteristics and Equations
Reflection of Sound
Audible Range and Uses of Sound
Chapter 2: Lenses
Lens Types and Terms
Image Formation and Equations
Optical Instruments
Chapter 3: The World of Colours and Vision
Light and Dispersion
Colours of Light and Dyes
Vision and Colour Perception
The Human Eye
Chapter 4: Magnetic Effect of Electric Current
Fundamentals of Electromagnetism
Motor Principle and Devices
Part 2
Chapter 5: Electric Energy: Consumption and Conservation
Heating Effect and Joule's Law
Electric Power and Energy Consumption
Conservation and Environmental Impact
Chapter 6: Electromagnetic Induction in Daily Life
Induced Current and EMF
Generators and Power Stations
Transmission and Transformers
Household Electrical Safety
Chapter 7: Mechanical Advantage in Action
Simple Machines and Mechanical Advantage
Levers
Other Simple Machines
PHYSICS: X Standard
Part 1
Chapter 1: Sound Waves
Oscillations and Wave Characteristics
• Oscillation: A periodic motion where an object moves to and fro at regular intervals of time about its equilibrium position1.
• One Oscillation: Completed when the body returns to its initial
position in the same direction from where it started (e.g., A → B and
returns to A)23.
• Amplitude (a): The magnitude of maximum displacement to one side from the equilibrium position. SI unit is metre (m)3.
• Period (T): The time taken for one oscillation. SI unit is second (s)2.
• Frequency (f): The number of oscillations in one second. SI unit is hertz (Hz)4.
• Relation between Period and Frequency: Frequency is the reciprocal of
the period, f=1/T5. As the period increases, frequency decreases5.
• Practical Units of Frequency: 1 kilohertz (kHz) = 1000 Hz (103 Hz); 1 megahertz (MHz) = 1000000 Hz (106 Hz)6.
• Natural Frequency: The innate frequency at which an object vibrates freely6.
• Factors influencing Natural Frequency: Length of the object, size of the object, elasticity, and nature of the material6.
Vibration Phenomena
• Forced Vibration: The vibration of an object induced by an external
vibrating object (e.g., a table vibrating when a tuning fork stem is
pressed on it)7.
• Resonance: Occurs when the natural frequency of the forcing object and
that of the forced object are equal. Objects undergoing resonance
vibrate with maximum amplitude8.
• Applications of Forced Vibration and Resonance: MRI scanning, radio
tuning, musical instruments (guitar, violin, stethoscope), megaphones,
horns, trumpets, and nagaswarams9.
Wave Motion and Types
• Wave Motion: The continuous propagation of energy from one part to the
other parts through oscillations10. It is a mode of transfer of
energy10.
• Mechanical Waves: Waves that require a medium for transmission (e.g., sound waves, seismic waves)11.
• Electromagnetic Waves: Waves that do not require a medium for transmission (e.g., radio waves, visible light, X-rays)11.
• Longitudinal Waves: Waves in which the particles in the medium vibrate
parallel to the direction of wave propagation1213. Sound is a
longitudinal wave14.
◦ Compressions (C): Regions of high pressure where air molecules decrease in distance14.
◦ Rarefactions (R): Regions of low pressure14.
• Transverse Waves: Waves in which the particles of a medium vibrate
perpendicular to the direction of wave propagation1315. Electromagnetic
waves are transverse waves16.
◦ Crests: Elevated portions from the equilibrium position15.
◦ Troughs: Lowest portions from the equilibrium position15.
Wave Characteristics and Equations
• Cycle: One complete oscillation of a particle in wave motion17.
• Wavelength (\lambda): The distance between two consecutive particles which are in the same phase of vibration17.
◦ For transverse waves: Distance between two consecutive crests or troughs17.
◦ For longitudinal waves: Distance between two consecutive compressions or rarefactions18.
◦ Unit: metre (m)18.
• Speed of Wave (v): The distance travelled by the wave in one second. Unit is m/s19.
• Speed-Frequency-Wavelength Relation: The speed of a wave is the
product of its wavelength and frequency: v=fλ20. When speed is constant,
frequency is inversely proportional to the wavelength (f∝1/λ)21.
Reflection of Sound
• Reflection of Sound: Sound waves reflect after striking objects22.
Smooth surfaces reflect sound more effectively than rough surfaces2223.
• Applications of Reflection: Soundboards and curved ceilings in halls are used to reflect sound and spread it23.
• Multiple Reflection of Sound: Reflected sound waves get reflected again24.
• Echo: The sound heard after a while due to the reflection of the initial sound25.
◦ Persistence of Hearing: The auditory experience produced by a sound persists for about 1/10 of a second25.
◦ Minimum Distance for Echo: For an echo to be heard distinctly (in air,
350 m/s), the reflecting surface must be at least 17.5 m away26.
• Reverberation: The lingering of sound, even after the original sound has ceased, due to the multiple reflection of sound27.
Audible Range and Uses of Sound
• Limits of Audibility (Human): For a person with normal hearing, the range is about 20 Hz to 20,000 Hz (20 kHz)28.
• Infrasonic: Sound with a frequency below 20 Hz28.
• Ultrasonic: Sound with a frequency more than 20,000 Hz28.
• Uses of Ultrasonic Waves:
◦ Medical diagnosis and treatment (crushing kidney stones, physiotherapy)29.
◦ Ultra sonography (taking images of internal organs)30.
◦ Cleaning spiral tubes, machine parts, electronic components30.
◦ In the device called SONAR (Sound Navigation and Ranging) to find the distance to underwater objects30.
• Seismic Waves: Waves that travel through the Earth's crust as a result
of earthquakes, volcanic eruptions, or massive explosions31.
• Tsunami: A series of gigantic ocean waves caused by the displacement of large volumes of water in the sea31.
Chapter 2: Lenses
Lens Types and Terms
• Lens: A transparent medium where each refracting surface is part of the spheres32. A lens has two refracting surfaces32.
• Convex Lens (Converging Lens): Thicker in the middle and thinner at the edges3334. It converges light rays33.
• Concave Lens (Diverging Lens): Thinner in the middle and thicker at the edges34. It diverges light rays35.
• Optic Centre (O): The midpoint of a lens36.
• Centres of Curvature (C_1, C_2): The centres of the spheres of which the refracting surfaces are parts36.
• Optic Axis: The imaginary line passing through the centres of curvature and the optic centre36.
• Aperture: The area of the lens through which light passes37.
• Principal Focus (F) - Convex: The point on the optic axis where light
rays near and parallel to the optic axis converge after refraction.
Considered real38.
• Principal Focus (F) - Concave: The point on the optic axis from which
light rays near and parallel to the optic axis appear to diverge after
refraction. Considered virtual3940.
• Focal Length (f): The distance from the optic centre of the lens to the principal focus41.
Image Formation and Equations
• Real Image: Images that can be projected on a screen40.
• Virtual Image: Images that cannot be captured on a screen but can only be seen4243.
• Image Formation by Convex Lens:
◦ If the object is placed between F and the lens, the image is formed on
the same side, and is Erect, Virtual, and Magnified4244.
◦ If the object is beyond F, the images formed are Real and Inverted35.
• Image Formation by Concave Lens: The image formed is always virtual,
diminished, and erect, located between F and the lens on the same side
of the object45.
• Cartesian Sign Convention:
◦ All distances should be measured from the optic centre (O)46.
◦ Distances in the same direction as the incident ray are positive; opposite direction is negative46.
◦ Distances measured above the optic axis are positive; below are negative46.
• Lens Equation: f1=v1−u1 (where u is object distance, v is image distance, and f is focal length)47.
• Magnification (m): The ratio of the height of the image (hi) to the
height of the object (ho), or the ratio of the distance to the image
(v) to the distance to the object (u)48.
◦ m=hohi=uv48.
◦ Positive magnification means the image is erect (Virtual); negative magnification means the image is inverted (Real)4950.
• Power of Lens (P): The ability of a lens to converge or diverge light
rays51. It is the reciprocal of the focal length (P=1/f)5253.
◦ SI unit: Dioptre (D)53.
◦ The power of a convex lens is positive52; the power of a concave lens is negative52.
Optical Instruments
• Compound Microscope: Magnifies micro objects52.
◦ Objective: Lens placed close to the object; has a shorter focal length5354.
◦ Eyepiece: Lens through which the image is observed; has a greater focal length5354.
◦ Objective forms a large, real, inverted image which acts as the object
for the eyepiece, which then forms a large and virtual image55.
• Refracting Telescope: Used to see distant objects clearly56.
◦ Objective Lens: Has a longer focal length and greater aperture5758.
◦ Eyepiece Lens: Has a shorter focal length and lesser aperture5758.
◦ The objective forms a small, real, and inverted image of the distant object; the eyepiece views this image virtually59.
Chapter 3: The World of Colours and Vision
Light and Dispersion
• Refraction in Prism: When a light ray enters and leaves a prism, it
deviates towards the base of the prism due to refraction60.
• Dispersion of Light: The phenomenon of splitting up of a composite
light (like white light/sunlight) into its component colours (VIBGYOR -
Violet, Indigo, Blue, Green, Yellow, Orange, Red)6162. The orderly
arrangement of these colours is called the spectrum61.
• Deviation and Wavelength: The extent of deviation depends on the wavelength of light (λ)6364.
◦ Red light (longest λ) deviates the least64.
◦ Violet light (shortest λ) deviates the most64.
• Rainbow Formation: A natural phenomenon resulting from the combined
effect of refraction, dispersion, and internal reflection of sunlight
through water droplets65. A rainbow is always formed in a direction
opposite to the sun66.
• Electromagnetic Spectrum: The orderly distribution of electromagnetic
radiations (Gamma rays, X-rays, UV, Visible light, IR, Microwaves, Radio
waves). They travel through vacuum at 3×108 m/s6768.
Colours of Light and Dyes
• Primary Colours of Light: Red, Green, and Blue (RGB). All coloured lights can be created using them69.
• Secondary Colours of Light: Formed by combining any two primary colours of light69. (e.g., Red + Green = Yellow)70.
• White Light: Produced by combining red, green, and blue colours of the same intensity70.
• Complementary Colours: Pairs of colours (a secondary colour and the
primary colour not present in it) that combine to form white light
(e.g., Yellow + Blue)71.
• Primary Dyes: Cyan, Magenta, and Yellow (CMY)72. Combination of Cyan + Yellow + Magenta yields Dark72.
Vision and Colour Perception
• Persistence of Vision: The visual experience of an object persists for about 1/16 of a second after the object is removed72.
• Colour of Transparent Objects (Filters): A filter of a specific colour
transmits light of its own colour and its component colours from white
light, blocking the others7374.
• Colour of Opaque Objects: An object appears in the colour of the light that is reflected from it to our eyes7576.
◦ A surface reflecting all colours appears white in white light77.
◦ A surface absorbing all colours appears dark77.
• Scattering of Light: Irregular and partial directional deviation of
light when it encounters microscopic particles in a medium7879.
◦ Blue Sky: Light with shorter wavelengths (violet, indigo, blue)
undergoes maximum scattering in the atmosphere, spreading the blue light
across the sky80.
◦ Red Sun (Sunrise/Sunset): Sun's rays travel a longer distance through
the atmosphere. Since red light undergoes the least scattering, it
remains prominent in the light reaching the Earth81.
• Tyndall Effect: When light passes through a colloidal liquid or
suspension, the path of light becomes visible due to scattering by tiny
particles82.
The Human Eye
• Power of Accommodation: The ability of the eye to change the curvature
(and thus focal length) of the lens to adjust so that the image of the
object always falls clearly on the retina83.
◦ Ciliary muscles control lens curvature and focal length84.
• Near Point: The nearest point at which an object can be seen clearly (25 cm for healthy eyes)85.
• Far Point: The farthest point at which an object can be seen clearly (considered infinity)85.
• Short Sightedness (Myopia): Inability to see distant objects clearly
(image forms in front of the retina)8586. Associated with a larger
eyeball and more powerful lens8687. Rectified using a concave lens87.
• Long Sightedness (Hypermetropia): Inability to see nearby objects
clearly (near point > 25 cm)8788. Associated with a smaller eyeball
and less powerful lens88. Rectified using a convex lens89.
• Presbyopia: Reduction in the efficiency of ciliary muscles in older
people, leading to less power of accommodation and an increased near
point89.
Chapter 4: Magnetic Effect of Electric Current
Fundamentals of Electromagnetism
• Magnetic Effect of Electricity: A magnetic field is formed around a
current carrying conductor, which can exert a force on a magnetic
needle, causing it to deflect9091.
• Direction of Magnetic Field: Depends on the direction of the
current92. Reversing the direction of the current reverses the direction
of the magnetic field93.
• Right Hand Thumb Rule (Straight Conductor): Imagine holding a
conductor with your right hand so that the thumb points in the direction
of the electric current; the curled fingers indicate the direction of
the magnetic field9495.
• Solenoid: An insulated conductor wound in a spiral shape96.
• Factors Influencing Solenoid Magnetic Strength: The number of turns of
the conductor per unit length and the magnitude of the current97.
Magnetic strength is significantly increased by placing a soft iron core
inside98.
• Solenoid Polarity (Right Hand Rule): If the fingers curl around the
coils in the direction of the current, the thumb points towards the
north pole99. Clockwise current at an end indicates a South Pole;
anticlockwise current indicates a North Pole97.
• Electromagnet: A device that creates a magnetic field using
electricity. Magnetism is temporary (only when current is flowing) and
its strength and polarity can be varied97100.
Motor Principle and Devices
• Motor Principle: A current carrying conductor, which is free to move
and is placed in a magnetic field, exhibits a tendency to deflect101.
• Direction of Force: The direction of the force experienced by the
conductor is influenced by the direction of the electric current and the
magnetic field102. If the direction of the current or the magnetic
field is reversed, the motion is reversed102.
• Fleming's Left Hand Rule: Used to determine the direction of the
force/motion (thumb) experienced by a conductor carrying current (second
finger) placed in a magnetic field (first finger)103104.
• Electric Motor: A device that converts electric energy into mechanical energy based on the motor principle101105.
◦ Main Parts: Armature, Field Magnet, Split Rings (Commutator), and Brushes106.
◦ Split Ring Commutator: Mechanism used to change the direction of
current flow through the armature after every half rotation, ensuring
continuous rotation in the same direction107.
• Moving Coil Loudspeaker: Operates based on the motor principle108. It
converts electric signals (audio signals) into sound waves (mechanical
energy)108. Electric signals passing through the voice coil (placed in a
magnetic field) cause the coil and the attached diaphragm to vibrate,
reproducing sound108.
Part 2
Chapter 5: Electric Energy: Consumption and Conservation
Heating Effect and Joule's Law
• Effect of Electric Current: The useful form of energy into which an appliance mainly converts electric energy109.
• Heating Effect of Electric Current: The conversion of electric energy mainly into heat energy110.
• Joule Heating (Ohmic Heating): The process of producing heat when electricity flows through a conductor111.
• Heating Element: The part used to produce heat, typically made of the alloy nichrome111.
• Characteristics of Nichrome: High oxidation resistance, ability to
provide heat energy for a long time in a red hot state, and high
resistivity112.
• Resistivity (\rho): The resistance of a conductor with 1 m2 area of cross section and 1 m length. Unit is ohmmetre (Ωm)113.
• Joule's Law: The quantity of heat produced (H) is directly
proportional to the square of the current (I2), the resistance (R), and
the time (t)114.
◦ Equation: H=I2Rt. SI unit is joule (J)114.
• Alternative Heat Equations (derived from Ohm's Law V=IR): H=RV2t and H=VIt115.
• Voltage and Resistance (Constant V): If voltage is constant,
decreasing resistance increases the current, hence increasing the
quantity of heat produced116.
Electric Power and Energy Consumption
• Electric Power (P): The quantity of work done (or electric energy
converted) by an electrical appliance per unit time (rate of
work)117118.
• Power Equations: P=tW=I2R=RV2=VI119120.
• Heat from Power: If power is known, H=Pt119.
• Power Marking: The marked power (e.g., at 230 V in India) is available
only when the appliance operates at the specified voltage120121.
• Power Units: Power consumed is in watt (W) (e.g., bulb); power supplied is in volt ampere (VA) (e.g., UPS, solar panel)122.
• Electric Energy Measurement: Measured in kilowatt hour (kWh) units by a watt hour meter123.
• Commercial Unit of Electric Energy: Kilowatt hour (kWh) or unit123124.
◦ 1 kWh (1 unit): The energy consumed by an appliance with 1000 W (1 kW) power in one hour124.
◦ Joule equivalent: 1 kWh = 3,600,000 J or 3.6×106 J125.
◦ Formula for kWh: 1000Power in watt×time in hour126.
Conservation and Environmental Impact
• Energy Star Rating: Indicates energy efficiency (5 stars = highest
efficiency)127. Higher rated appliances have lower electricity bills and
lower environmental impact127.
• TOD Billing (Time Of the Day): An innovative billing system introduced
by KSEB where charges vary based on the time zone (peak hours: 6 pm to
10 pm have the highest charge)128.
• Energy Crisis: The increase in demand for energy and the decrease in availability129.
• Solar Cells: Devices that convert solar energy into electric
energy130. Solar panels are arrangements of many solar cells130.
Benefits include producing required electricity and reducing
environmental pollution131.
• Global Warming: Caused by increasing greenhouse gases (e.g., carbon dioxide, methane)131132.
• Carbon Footprint: The quantity of greenhouse gases emitted by
individuals or organizations, expressed as equivalent to the measure of
carbon dioxide131. Reducing domestic energy consumption and using public
transport can reduce carbon footprint133.
Chapter 6: Electromagnetic Induction in Daily Life
Induced Current and EMF
• Electromagnetic Induction: The phenomenon where an emf is induced in a
closed circuit whenever the magnetic flux linked with the circuit
changes134.
• Induced EMF/Current: The electromotive force developed is the induced emf; the current produced is the induced current134.
• Factors Increasing Induced EMF/Current: Increasing the strength of the
magnet, increasing the number of turns per unit length of the coil, or
increasing the speed of relative motion between the magnet and
coil135136.
• Direct Current (DC): Current that flows only in one direction137.
• Alternating Current (AC): Current that continuously changes direction at regular intervals of time137.
Generators and Power Stations
• Generator: A device that converts mechanical energy into electric
energy based on the principle of electromagnetic induction138.
• AC Generator: Produces alternating current. Uses slip rings and brushes to transfer AC to the external circuit139140.
• DC Generator: Produces direct current. Uses a split ring commutator and brushes to transfer DC to the external circuit139140.
• Power Stations: Centres for large scale electricity generation141.
◦ Hydroelectric: Potential energy of water → Mechanical energy → Electric energy142143.
◦ Thermal: Chemical energy (fuel) → Heat energy → Mechanical energy → Electric energy142143.
◦ Nuclear: Nuclear energy → Heat energy → Mechanical energy → Electric energy142143.
Transmission and Transformers
• Energy Loss in Transmission: Occurs mainly in the form of heat
(H=I2Rt) when electricity is transmitted over long distances144.
• Minimising Loss: Use suitable metal wires with low resistivity (e.g.,
copper or aluminum)145146 and increase voltage to decrease current (as
P=VI) without changing the power146147.
• Mutual Induction: When two coils are near each other, and the current
in the first coil (primary) changes, the resulting change in magnetic
field induces an emf in the second coil (secondary)148.
• Transformer: A device that works on the principle of mutual induction to change AC voltage without changing power149.
• Step-up Transformer: Increases AC voltage (VS>VP). The secondary
coil has more turns than the primary coil (NS>NP)149150. Secondary
current is lower than primary current151.
• Step-down Transformer: Decreases AC voltage (VS<VP). The
secondary coil has fewer turns than the primary coil (NS<NP)149150.
Secondary current is higher than primary current151.
• Transformer Equation (Ideal): The ratio of voltages is equal to the
ratio of turns: VPVS=NPNS152153. Also, VPIP=VSIS (Primary
Power = Secondary Power)154.
• Power Distribution: Electricity is generated at 11 kV, stepped up
(e.g., to 220 kV) for long-distance transmission, and then stepped down
via distribution transformers (finally to 230 V for houses)155156.
Household Electrical Safety
• Household Wiring: Lines are distributed from the MCB board as branches157. Appliances are connected in parallel158.
• Wire Colours: Phase/Live (Red), Neutral (Black), Earth (Green)158.
• Short Circuit: Occurs when phase and neutral lines contact with negligible resistance, resulting in excessive current flow159.
• Overloading: Excessive current flow when a circuit carries more power
than its permissible limit (e.g., connecting a high-power appliance to a
normal plug)159160.
• Safety Fuse: Protects equipment from dangers of excessive current
(overloading, short circuits)161. Works based on the heating effect of
electricity161. Fuse wire has a relatively low melting point and is
connected in series to the phase line161162.
• MCB (Miniature Circuit Breaker): Used in branch circuits; operates
automatically (trips) due to excessive current. Works using the magnetic
effect and heating effect162.
• ELCB (Earth Leakage Circuit Breaker): Disconnects the circuit
automatically if there is current leakage, preventing electric shock163.
(RCCB is a safer modern alternative)164.
• Three Pin Plug and Earthing: Ensures safety for high power appliances by connecting the appliance to the earth wire158164.
Chapter 7: Mechanical Advantage in Action
Simple Machines and Mechanical Advantage
• Simple Machines: Devices that make exertion easier by changing the
magnitude of the effect of force or the direction of the force, or
both165.
• Six Types of Simple Machines: Lever, pulley, wheel and axle, inclined plane, screw, and wedge166.
• Effort (E): The force applied to a simple machine167.
• Load (L): The force the simple machine has to overcome167.
• Mechanical Advantage (MA): The ratio of the load to the effort168. MA=EffortLoad168. MA has no unit168.
• Work Done: There is no gain in work by using simple machines169.
Levers
• Lever: A rigid rod that can rotate around a fixed point called the fulcrum (F)170.
• Load Arm (LA): Perpendicular distance from the load (L) to the fulcrum (F)171.
• Effort Arm (EA): Perpendicular distance from the effort (E) to the fulcrum (F)171.
• Principle of a Lever (Equilibrium): Load × Load arm = Effort × Effort arm172.
• MA of Lever: MA=Load armEffort arm173.
• Lever Classification:
1. First Order Lever: Fulcrum (F) is between the load (L) and the effort
(E)174175. MA can be greater than one, equal to one, or less than
one175. Examples: common balance (MA=1), scissors, seesaw174.
2. Second Order Lever: Load (L) is between the effort (E) and the
fulcrum (F)175176. The effort arm is longer than the load arm177. MA is
always greater than one175177.
3. Third Order Lever: Effort (E) is between the load (L) and the fulcrum
(F)175178. The load arm is longer than the effort arm178. MA is always
less than one175178. Advantage: Helps to handle objects safely with
ease175. Examples: Tongs, fishing pole, forceps178.
Other Simple Machines
• Fixed Pulley: Rotates around a stationary axle; similar to a first
order lever (Load Arm = Effort Arm)179180. MA is one180. Advantage:
changes the direction of the applied force181.
• Movable Pulley: Moves with the load; similar to a second order lever181. The MA of a single movable pulley is 2182.
• System of Pulleys (n movable pulleys): MA is 2n in the first
system183. In the second system, MA is the total number of rope segments
supporting the load184.
• Wheel and Axle: Energy is transferred by applying effort to the wheel
(Radius R) to rotate the axle (Radius r)185. MA=rR (greater than
one)186.
• Gears: Mechanical devices using interlocking toothed wheels to
transfer motion or force187. Used to change speed (e.g., connecting
engine to a large toothed wheel decreases speed but increases
efficiency/torque)188.
• Inclined Plane: Used to lift objects to a height (h) by pushing them along a length (l)189.
◦ MA=Height of inclined plane (h)Length of inclined plane (l)190. A longer inclined plane provides more MA190.
• Wedge: A double inclined plane (e.g., knife, axe, chisel)191. Easier to use if it is longer and thinner191.
◦ MA=thickness of the wedge (h)length of the inclined plane of the wedge (l)191.
• Screw: Can be considered an inclined plane wrapped around a cylinder192.
◦ Pitch (h): The distance between two consecutive threads192.
◦ MA=pitch (h)length of one thread (l)192. write without page reference numbers
