9 Computer Note

 

9 computer note

December 31, 2025

S.No.                     Unit                                                         Page No.

1.            Computer System                                                     1

2.             Number System                                                     41

3.                 Block Programming                                         53

4.             Web Technology                                                 81

5.             Internet and Social Media                                 143

6.         Cyber Security and Digital Citizenship                 167

7.             Concept of Programming                                 185

1. Features of a Computer

1. Automatic – Works automatically as instructed by software.

2. Speed – Processes millions of instructions per second.

3. Accuracy – Produces correct results; errors occur only due to wrong input (GIGO) or faults (bugs).

4. Storage – Can store large amounts of data in devices like HDD, SSD, USB.

5. Diligence – Can perform tasks repeatedly without losing speed or accuracy.

6. Versatility – Can perform many tasks: calculation, designing, communication, research, and entertainment.

2. Functions of a Computer – IPOS

IPOS: Input → Process → Output → Storage

• Input: Enter data into the computer.

• Process: CPU processes data.

• Output: Display results.

• Storage: Save data for future use.

3. Applications of Computers

1. Education

   • Online learning, multimedia teaching, record-keeping, generating reports.

2. Communication

   • Email, video calls, social media, instant messaging.

3. Banking

   • Online banking, account management, statements, improved efficiency and security.

4. Medicine/Healthcare

   • Diagnosis (CT scans, ultrasounds, ECGs), patient records, surgery, medical research, simulations.

5. Entertainment

   • Gaming, music, movies, streaming platforms, digital art, social media.

6. Scientific Research

   • Weather forecasting, space exploration, simulations, analyzing big data.

7. Agriculture

   • Precision farming, GPS, drones, IoT, AI for efficient farming and decision-making.

Input, Output, CPU, Memory, and Storage

1. Input Devices

Devices used to enter data into a computer for processing.

Device	Function
Mouse	Handheld pointing device to click, drag, and scroll.
Keyboard	Type data; keys: alphabet, numeric, cursor, function, special keys.
Joystick	Control games; stick with buttons for direction and actions.
Microphone	Captures sound and converts to digital form.
Scanner	Converts physical documents/images to digital format.
Webcam	Captures real-time video and audio for streaming or conferencing.
Touchscreen	Display that responds to finger touch.
Touchpad	Laptop input pad for moving cursor, like a mouse.

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2. Central Processing Unit (CPU)

The brain of the computer that processes data.

Functions:

1. Fetching – Get instructions/data from memory.

2. Decoding – Understand instructions.

3. Executing – Perform operations.

4. Storing – Save results.

5. Managing Interrupts – Handle other device requests.

Components:

• Control Unit (CU) – Directs all parts of the computer.

• Arithmetic Logic Unit (ALU) – Performs calculations and logical operations.

• Registers – Small memory for immediate data and instructions.

3. Motherboard and Data Bus

• Motherboard: Main circuit board connecting all components.

• Data Bus: Pathway for transferring data between CPU, memory, and devices.

4. Computer Memory

Primary Memory (Main Memory)

• Directly accessible by CPU; stores data temporarily or permanently.

• RAM (Random Access Memory) – Volatile, read/write memory; cleared when power is off.

  • SRAM: Fast, no refresh, expensive, used for cache.

  • DRAM: Slower, needs refresh, cheaper, used in PCs.

• ROM (Read Only Memory) – Non-volatile, permanent; stores BIOS and firmware.

  • PROM: Programmed once, permanent.

  • EPROM: Reprogrammable using UV light.

  • EEPROM: Reprogrammable electronically.

• Cache Memory: High-speed memory between RAM and CPU for fast access.

• Registers: CPU storage for immediate processing.

Secondary Memory (Storage)

• Stores data permanently; slower than primary memory.

• Examples: Hard disk, SSD, optical disks, pen drives.

Memory Units: Bit → Nibble → Byte → KB → MB → GB → TB → PB → YB

5. Storage Devices

Device	Description
Hard Disk (HDD)	Magnetic disks; large capacity; slower than SSD.
SSD	Fast semiconductor storage; no moving parts.
CD/DVD/Blu-ray	Optical discs using laser to read/write data.
Flash Memory / Pen Drive	Portable, non-volatile, electrically erasable.
Cloud Storage	Online storage accessed via internet (Google Drive, Dropbox).

Comparison:

• HDD: Cheap, large, slower.

• SSD: Expensive, fast, reliable.

• Flash: Portable, fast, durable.

6. Output Devices

Convert processed data into human-readable form.

Device	Function
Monitor	Displays text, images, videos (soft copy).
Printer	Prints data on paper (hard copy); types: laser, inkjet, dot-matrix, 3D printer.
Speaker	Converts digital sound into audible sound.

7. Peripheral Devices & Ports

External devices that enhance computer functionality.

Port	Use
USB	Connect various devices, transfer data.
Type C	Reversible connector, fast charging, data transfer.
HDMI	Transmit high-definition audio/video.
VGA	Connect monitors/projectors (analog).
Ethernet	Wired network connection (LAN).
Audio	Connect speakers, microphones, headphones.

 Exercises (Q&A)

1. Write Full Forms of the Following Abbreviations

Q1. Write the full forms:
i. CPU – Central Processing Unit
ii. BIOS – Basic Input Output System
iii. HDD – Hard Disk Drive
iv. SSD – Solid State Drive
v. RAM – Random Access Memory
vi. CU – Control Unit
vii. USB – Universal Serial Bus
viii. ALU – Arithmetic Logic Unit
ix. MU – Memory Unit
x. PCB – Printed Circuit Board
xi. ROM – Read Only Memory
xii. PSU – Power Supply Unit
xiii. CMOS – Complementary Metal Oxide Semiconductor
xiv. CD – Compact Disc
xv. DVD – Digital Versatile Disc
xvi. KB – Kilobyte
xvii. MB – Megabyte
xviii. GB – Gigabyte
xix. TB – Terabyte
xx. YB – Yottabyte
xxi. PB – Petabyte
xxii. SRAM – Static Random Access Memory
xxiii. DRAM – Dynamic Random Access Memory
xxiv. VRAM – Video Random Access Memory
xxv. EPROM – Erasable Programmable Read-Only Memory
xxvi. EEPROM – Electrically Erasable Programmable Read-Only Memory
xxvii. rpm – revolutions per minute
xxviii. VDU – Visual Display Unit
xxix. LED – Light Emitting Diode
xxx. LCD – Liquid Crystal Display
xxxi. CPS – Characters Per Second
xxxii. LCM – Lines Per Minute
xxxiii. PPM – Pages Per Minute
xxxiv. Mbps – Megabits Per Second
xxxv. HDMI – High Definition Multimedia Interface
xxxvi. LAN – Local Area Network

2. Choose the Correct Answer

Q2.1. What is the primary function of the CPU in a computer system?
(a) Memory storage (b) Data input (c) Arithmetic and logic operations (d) Graphics rendering
Answer: (c) Arithmetic and logic operations

Q2.2. Which of the following is a volatile memory in a computer system?
(a) Hard Disk Drive (HDD) (b) Random Access Memory (RAM)
(c) Solid State Drive (SSD) (d) Cache Memory
Answer: (b) RAM

Q2.3. What does the term BIOS stand for?
(a) Basic Input Output System (b) Binary Input Output System
(c) Base Input Output Software (d) Basic Integrated Operating System
Answer: (a) Basic Input Output System

Q2.4. Which of the following is a secondary storage device?
(a) RAM (b) CPU (c) USB Flash Drive (d) Cache Memory
Answer: (c) USB Flash Drive

Q2.5. What is the role of the motherboard?
(a) Manage power supply (b) Connect all hardware components and provide communication (c) Execute software applications (d) Store data permanently
Answer: (b) Connect all hardware components and provide communication

Q2.6. What is the role of a monitor?
(a) Capture barcodes (b) Provide visual display of digital info
(c) Regulate power (d) Convert sketches to digital
Answer: (b) Provide visual display of digital info

Q2.7. What is the role of microphones?
(a) Capture barcodes (b) Record audio input
(c) Read magnetic stripes (d) Scan documents
Answer: (b) Record audio input

Q2.8. Primary function of a printer?
(a) Convert text to digital (b) Display graphics on screen (c) Produce hard copy of digital data (d) Record audio
Answer: (c) Produce hard copy of digital data

Q2.9. Primary function of microprocessor?
(a) Display graphics (b) Manage power (c) Control cooling system (d) Execute instructions and perform calculations
Answer: (d) Execute instructions and perform calculations

3. Short Answer Questions

Q3.1. What is the primary function of the CPU?
Answer: Executes instructions, performs calculations, and controls other computer components.

Q3.2. Difference between RAM and ROM:

• RAM: Temporary, volatile memory, used to run programs.

• ROM: Permanent, non-volatile memory, stores essential instructions (BIOS).

Q3.3. How does a hard drive differ from RAM?

• Hard drive: Permanent, slow storage for large data.

• RAM: Temporary, fast memory for active programs.

Q3.4. Role of motherboard:
Answer: Connects CPU, memory, storage, and peripherals; manages communication between components.

Q3.5. What is cache memory and why is it important?
Answer: High-speed memory storing frequently used data; improves CPU processing speed.

Q3.6. Define a bus in computer architecture:
Answer: A pathway for transferring data, instructions, and signals between components.

Q3.7. Purpose of input device and examples:
Answer: Enter data into computer. Examples: Keyboard, mouse, scanner, microphone.

Q3.8. What is a peripheral device and how does it enhance a computer?
Answer: External hardware providing extra functions. Examples: Printer, speakers, USB drives.

4. Long Answer Questions

Q4.1. Explain the architecture of a computer system.
Answer:

• CPU: Processes instructions and calculations.

• Memory: Stores temporary (RAM) and permanent data (ROM/HDD).

• Input devices: Enter data (keyboard, mouse).

• Output devices: Show results (monitor, printer).

• Storage devices: Hold large, permanent data (HDD, SSD, CD/DVD).

Q4.2. Role of Operating System (OS):

• Manages hardware and software resources.

• Provides user interface and file management.

• Examples: Windows, Linux, macOS.

• Functions: Memory management, process scheduling, device management, security.

Q4.3. Differentiate primary and secondary memory:

Feature	Primary Memory	Secondary Memory
Communication	Direct with CPU	Indirect with CPU
Volatility	Volatile/non-volatile	Non-volatile
Storage Capacity	Low	High
Speed	Fast	Slow
Example	RAM, ROM, Cache	HDD, SSD, Pen Drive

Q4.4. Role of cache memory, RAM, and storage devices:

• Cache: Stores frequently used data for CPU, increases speed.

• RAM: Holds active programs for CPU access.

• Storage: Stores permanent files and software.

• Together: Ensure fast, reliable computer performance.

Q4.5. CPU Architecture:

• Control Unit (CU): Directs CPU operations.

• Arithmetic Logic Unit (ALU): Performs arithmetic and logic operations.

• Registers: Small memory for immediate data/instructions.

• Fetch-Decode-Execute Cycle: CPU fetches → decodes → executes → stores results.

1.9 Computer Software – Simple Notes

Definition:
Computer software is a set of instructions, programs, or data that allow a computer to perform specific tasks. It works with hardware to enable applications and user interactions.

Types of Computer Software:

1. System Software – Manages computer operations and hardware.

2. Application Software – Performs specific user tasks.

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A. System Software

• Definition: Software that forms the backbone of computer operations and acts as a bridge between user and hardware.

• Functions: Organizes files, manages hardware resources, and provides a platform for application software.

• Categories:

  1. Operating System (OS)

     • Controls and manages overall computer operation.

     • Acts as an interface between user, hardware, and software.

     • Loaded first into RAM when PC starts.

     • Examples: Windows, Linux, MacOS, Android, Ubuntu.

  2. Language Processor

     • Translates high-level or assembly programs into machine language.

     • Types: Assembler, Interpreter, Compiler.

  3. Utility Software

     • Maintains hardware and data.

     • Tasks: Backup, virus removal, disk management, file transfer.

     • Examples: WinRAR, CCleaner, Antivirus, Disk Defragmenter.

  4. Device Drivers

     • Programs that control and manage specific hardware.

     • Examples: Printer driver, sound card driver, display card driver.

B. Application Software

• Definition: Programs designed for specific user tasks.

• Types:

  1. Packaged/General Purpose Software

     • Ready-made software for general users.

     • Examples: MS Office, Photoshop, CorelDraw, VLC, Zoom.

  2. Customized/Tailored Software

     • Designed for specific organizational or individual needs.

     • Examples: Hospital Management Software, SEE Result Processing, Banking Software.

Open Source vs Proprietary Software

Feature	Open Source Software (OSS)	Proprietary Software (CSS)
Source Code	Publicly accessible	Restricted to creator
Modification	Can be modified freely	Only by creator/vendor
Cost	Free or nominal	Paid license required
Flexibility	High	Limited
Examples	Linux, Android, OpenOffice	Windows OS, Adobe Photoshop, iTunes

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System vs Application Software

Feature	System Software	Application Software
Purpose	Manages computer resources	Fulfills user tasks
Language	Low-level / machine language	High-level / 4GL
Execution	Runs on startup until shutdown	Runs on user demand
Dependency	Independent	Needs system software
Importance	Crucial for system function	Not crucial for system

Mobile and Web Applications

• Mobile Apps: Programs for smartphones/tablets using features like touchscreen, GPS, camera.

  • Examples: WhatsApp, Spotify, Google Maps.

• Web Applications: Programs running on web browsers via the internet.

• No installation needed; accessible on any device with browser.

• Examples: Gmail, Google Docs, Facebook.

1. Full Forms of Abbreviations

Abbreviation	Full Form
i. OS	Operating System
ii. CUI	Command User Interface
iii. DOS	Disk Operating System
iv. GUI	Graphical User Interface
v. SPSS	Statistical Package for the Social Sciences
vi. OSS	Open Source Software
vii. SQL	Structured Query Language
viii. HTML	HyperText Markup Language
ix. CSS	Cascading Style Sheets

2. Choose the Correct Answer

i. What is the purpose of an operating system in a computer system?
Answer: a. Manage hardware resources and provide a user interface

ii. Which type of software is designed to perform a specific task, such as word processing or spreadsheet calculations?
Answer: b. Application software

iii. What is software?
Answer: b. Instructions that tell a computer what to do

iv. Which of the following is an example of application software?
Answer: a. Microsoft Word

v. What is the role of the operating system?
Answer: b. To manage hardware and software resources

vi. Which of the following is not software?
Answer: a. Keyboard

3. Short Answer Questions

a. What does the term “open source” mean in software?
Answer: Open source software is software whose source code is publicly accessible. Anyone can view, modify, and use it freely.

b. How does open-source software differ from proprietary software?
Answer: Open-source software allows free access and modification of code, while proprietary software is owned by a company or individual, and its source code is restricted. Users need a license to use it.

c. What is system software, and what role does it play in a computer system?
Answer: System software manages computer hardware and provides a platform for application software. It includes operating systems, utility software, device drivers, and language processors.

d. Define application software and provide examples of common applications.
Answer: Application software is designed to perform specific user tasks, such as word processing, photo editing, or communication. Examples: Microsoft Word, Photoshop, Excel, Zoom, VLC Media Player.

e. What is the purpose of utility software, and give examples of utilities?
Answer: Utility software maintains and optimizes the computer system. Examples: Antivirus programs, Disk Defragmenter, Backup software, CCleaner, WinRAR.

4. Long Answer Questions

a. Explain the types of computer software with their respective functions.
Answer:

1. System Software: Manages hardware and system resources, acts as a bridge between hardware and users. Includes:

   • Operating System (OS): Manages hardware, software, and user interface. Examples: Windows, Linux, MacOS.

   • Utility Software: Maintains system performance (Backup, Antivirus, Disk Management).

   • Language Processors: Translate code from high-level language to machine language (Assembler, Compiler, Interpreter).

   • Device Drivers: Control specific hardware devices (Printer driver, Sound card driver).

2. Application Software: Designed to perform specific tasks for users. Includes:

   • Packaged Software: Ready-made software for general users (MS Office, Adobe Photoshop, VLC).

   • Customized Software: Developed for specific organizations or individuals (Hospital Management Software, Billing Software, Banking Software).

b. Differentiate between system software and application software with respective roles.

Feature	System Software	Application Software
Purpose	Manage hardware and system resources	Perform user-specific tasks
Dependency	Can run independently	Needs system software to run
Execution	Starts with the computer and runs continuously	Runs when user starts it
Examples	Windows OS, Linux, Device Drivers	MS Word, Photoshop, Zoom

c. Differentiate between open source and proprietary software models with examples.

Feature	Open Source Software (OSS)	Proprietary Software (CSS)
Source Code	Publicly accessible	Restricted, only creator/vendor can access
Modification	Can be modified freely	Cannot be modified by users
Cost	Free or minimal	Paid license required
Flexibility	High, encourages innovation	Limited
Examples	Linux, Android, OpenOffice	Windows OS, Adobe Photoshop, iTunes

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d. Explain the concept of utility software and its role in enhancing the performance and functionality of a computer system.
Answer:
Utility software is system software designed to maintain, optimize, and secure a computer. It performs tasks like removing viruses, managing files, backing up data, and cleaning the system. By maintaining hardware and software efficiency, it ensures smooth operation, prevents system crashes, and improves overall performance. Examples include antivirus software (Avira, Norton), disk defragmenters, CCleaner, WinRAR, and backup tools.

Number System

a) What is a digit?

A digit is a single symbol used to write numbers in any number system.
Examples:

• In decimal system: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

• In binary system: 0 and 1

So, a digit is the smallest unit of a number.

b) What is a computer word?

A computer word is a fixed number of bits that a computer processes as a single unit.
It is the natural size of data handled by the CPU.

Examples:

• 8 bits = 1 byte

• 16 bits = 1 word (in old systems)

• 32 bits or 64 bits = 1 word (in modern computers)

c) Define the base or radix of the number system.

The base or radix of a number system is the total number of different digits used in that system.

Examples:

• Binary system → Base = 2 (digits: 0, 1)

• Decimal system → Base = 10 (digits: 0–9)

• Octal system → Base = 8 (digits: 0–7)

• Hexadecimal system → Base = 16 (digits: 0–9, A–F)

d) Which language is used by computer systems, smartphones, and tablets?

All computer systems, smartphones, and tablets internally use machine language (binary language).
This language consists of only two digits: 0 and 1.

Decimal number system

 The decimal number system is the common number system we use in our lives. It has a base of 10 since it uses digits ranging from 0 to 9. In this system, each digit’s position represents a distinct power of 10, which includes units, tens, hundreds, thousands, and so on. For example, the decimal number 719 consists of the digit 9 in the units position, 1 in the tens position, and 7 in the hundreds position. (719)10 = (7 × 100) + (1 × 10) + (9 × 1) = (7 × 102) + (1 × 101) + (9 × 100) = 700 + 10 + 9 = 719 

 Binary number system 

 The binary number system uses only two digits: 0 and 1. Thus, it is a base-2 number system. It is used by computers. For example, (110111)2 is a binary number.

Octal number system 

 The octal number system is the base-8 number system that uses 8 digits (0 to 7). Some examples of octal numbers are (207)8 , (5706)8 , (601022)8 , etc. 

 Hexadecimal number system 

 The hexadecimal number system is the base-16 number system that uses 16 symbols, i.e., 10 digits:0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 6 letters: A, B, C, D, E, F.

 The letters from A to F represent the values 10 to 15 respectively.

Application of number system conversion 

 Number system conversion is important in many fields, especially in computer science and digital technology. Computers use binary code to process information, so it’s essential to understand how to convert between binary, decimal, octal, and hexadecimal systems.

 Binary calculation 

 There are four main types of binary calculation: 

 i. Binary addition, 

 ii. Binary subtraction,

 iii. Binary multiplication and

 iv. Binary division.

                                                                   Binary Table

Exercises

1. Choose the correct option

i. What is the result of the binary addition: 1101 + 1011?

a. (11010)₂
b. (11000)₂ ✔
c. (11110)₂
d. (11101)₂

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ii. When adding two binary numbers, what is the carrying value in binary addition?

a. 100
b. 1
c. 10 ✔
d. 11

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iii. In binary multiplication, what is the result when multiplying any binary digit by 0?

a. 1
b. 11
c. 0 ✔
d. The original digit

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iv. What is the base of the octal number system?

a. 2
b. 7
c. 8 ✔
d. 10

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v. What is the binary equivalent to the octal number 64?

a. (110100)₂ ✔
b. (1101111)₂
c. (1110001)₂
d. (11000101)₂

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vi. In the hexadecimal system, what does the symbol ‘A’ represent?

a. 11
b. 12
c. 10 ✔
d. 13

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2. Answer these questions

a) What is a number system?

A number system is a method of representing numbers using a set of digits and a specific base.

b) Define the base or radix of the number system.

The base or radix is the total number of different digits used in a number system.

c) List out the different types of number systems.

Binary, Octal, Decimal, and Hexadecimal.

d) What is a hexadecimal number system? Write down its symbols.

The hexadecimal system has base 16.
Symbols: 0–9 and A, B, C, D, E, F.

3. Calculate the following

a) Perform the following binary addition

i. (11110)₂ + (1001)₂ = (101111)₂
ii. (1011)₂ + (1001)₂ = (10100)₂
iii. (101011)₂ + (11011)₂ = (1000110)₂
iv. (1010)₂ + (110)₂ = (10000)₂
v. (101001)₂ + (1110)₂ = (110111)₂
vi. (100001)₂ + (100011)₂ = (1000100)₂
vii. (100111)₂ + (11010)₂ = (1000001)₂
viii. (110001)₂ + (100101)₂ = (1010110)₂

b) Perform the following binary subtraction

i. (1100)₂ – (1001)₂ = (0011)₂
ii. (1001)₂ – (110)₂ = (0011)₂
iii. (11101)₂ – (1010)₂ = (10011)₂
iv. (101100)₂ – (10011)₂ = (11101)₂
v. (11111)₂ – (10110)₂ = (01001)₂
vi. (110011)₂ – (10100)₂ = (100111)₂
vii. (100100)₂ – (1110)₂ = (010110)₂
viii. (1000001)₂ – (10101)₂ = (101100)₂

4. Convert the given numbers as indicated

a) Decimal to Binary Conversion

i. Convert (56)₁₀ to binary.
56₁₀ = 111000₂

ii. Convert (78)₁₀ to binary.
78₁₀ = 1001110₂

iii. Convert (123)₁₀ to binary.
123₁₀ = 1111011₂

iv. Convert (345)₁₀ to binary.
345₁₀ = 101011001₂

v. Convert (540)₁₀ to binary.
540₁₀ = 1000011100₂

vi. Convert (572)₁₀ to binary.
572₁₀ = 1000111100₂

vii. Convert (546)₁₀ to binary.
546₁₀ = 1000100010₂

viii. Convert (1098)₁₀ to binary.
1098₁₀ = 10001001010₂

ix. Convert (2103)₁₀ to binary.
2103₁₀ = 100000110111₂

x. Convert (445)₁₀ to binary.
445₁₀ = 110111101₂

b) Binary to Decimal Conversion

i. Convert (1101)₂ to decimal.
1101₂ = 13₁₀

ii. Convert (1010)₂ to decimal.
1010₂ = 10₁₀

iii. Convert (10010)₂ to decimal.
10010₂ = 18₁₀

iv. Convert (10110)₂ to decimal.
10110₂ = 22₁₀

v. Convert (101001)₂ to decimal.
101001₂ = 41₁₀

vi. Convert (11100111)₂ to decimal.
11100111₂ = 231₁₀

vii. Convert (111100)₂ to decimal.
111100₂ = 60₁₀

viii. Convert (10010011)₂ to decimal.
10010011₂ = 147₁₀

ix. Convert (1011100)₂ to decimal.
1011100₂ = 92₁₀

x. Convert (100110)₂ to decimal.
100110₂ = 38₁₀

c) Decimal to Octal Conversion

i. (69)₁₀ = 105₈
ii. (216)₁₀ = 330₈
iii. (767)₁₀ = 1377₈
iv. (79)₁₀ = 117₈
v. (443)₁₀ = 673₈
vi. (413)₁₀ = 635₈
vii. (765)₁₀ = 1375₈
viii. (1334)₁₀ = 2466₈
ix. (1825)₁₀ = 3441₈
x. (2783)₁₀ = 5327₈

d) Octal to Decimal Conversion

i. (124)₈ = 84₁₀
ii. (242)₈ = 162₁₀
iii. (333)₈ = 219₁₀
iv. (763)₈ = 499₁₀
v. (103)₈ = 67₁₀
vi. (451)₈ = 297₁₀
vii. (3401)₈ = 1793₁₀
viii. (1045)₈ = 549₁₀
ix. (438)₈ = Invalid octal number
x. (611)₈ = 393₁₀

e) Decimal to Hexadecimal Conversion

i. (55)₁₀ = 37₁₆
ii. (540)₁₀ = 21C₁₆
iii. (225)₁₀ = E1₁₆
iv. (880)₁₀ = 370₁₆
v. (2046)₁₀ = 7FE₁₆
vi. (2024)₁₀ = 7E8₁₆
vii. (6678)₁₀ = 1A16₁₆

f) Hexadecimal to Decimal Conversion

i. (56)₁₆ = 86₁₀
ii. (67)₁₆ = 103₁₀
iii. (558)₁₆ = 1368₁₀
iv. (B74)₁₆ = 2932₁₀
v. (20D3)₁₆ = 8403₁₀
vi. (DEF)₁₆ = 3567₁₀
vii. (6E3)₁₆ = 1763₁₀
viii. (63F)₁₆ = 1599₁₀

g) Binary to Hexadecimal Conversion

i. (1000110)₂ = 46₁₆
ii. (11001)₂ = 19₁₆
iii. (1111000)₂ = 78₁₆
iv. (11110000111)₂ = 787₁₆
v. (101010110)₂ = 156₁₆
vi. (1110010110)₂ = 396₁₆
vii. (11011001)₂ = D9₁₆
viii. (1001100)₂ = 4C₁₆

h) Hexadecimal to Binary Conversion

i. (D4)₁₆ = 11010100₂
ii. (643)₁₆ = 011001000011₂
iii. (189)₁₆ = 000110001001₂
iv. (2BF)₁₆ = 001010111111₂
v. (A9F)₁₆ = 101010011111₂
vi. (FACE)₁₆ = 1111101011001110₂
vii. (FB4)₁₆ = 111110110100₂
viii. (1B2)₁₆ = 000110110010₂

What is Block Programming?

Block Programming is a type of programming where you create programs by dragging and dropping blocks instead of typing code.

Each block looks like a puzzle piece and fits only in the correct place. This helps beginners avoid errors and learn programming easily.

Block programming is made up of two words: “Block” and “Programming”. Blocks are like puzzle pieces that you can join to form a beautiful picture. On the other hand, programming is a way of giving human instructions to a computer or electronic device about what they should do.

Block programming combines both these elements to provide a user friendly way to programming. 

 Concept of Block programming 

 Block programming is a popular programming language made for beginners, especially children, to teach them the basics of programming by using colorful blocks to build computer programs, videos, and games. It supports the use of graphics, animation, and sound without the need to understand complex programming languages. Some examples of block programming platforms are Scratch, Blockly, and Snap

Examples of Block Programming Languages

• Scratch

• MIT App Inventor

• MakeCode

• Tynker

 Features of Block Programming

Feature	Explanation
Drag and Drop	You move blocks with the mouse.
No Syntax Error	Blocks fit only where they are correct.
Visual	Programs are shown in colorful blocks.
Easy to Learn	Suitable for beginners and school students

Advantages of Block Programming

a) No syntax problem
Users do not need to worry about grammar or syntax like other programming languages.

b) Focus on creativity and logic
Users get more time to think about creativity, logic building, and problem-solving skills.

c) Less typing error
There are very few chances of human typing mistakes because users do not write codes manually.

d) Colorful and attractive
Block programming is colorful, visually appealing, and engaging for beginners and children.

e) Easy transition to text programming
Block programming provides an interactive way to learn concepts so users can easily shift to text-based languages in the future.

Applications of Block Programming

Block programming is widely used because it is simple and user-friendly.

a) Educational purpose

Used in schools to teach coding concepts.
It builds a strong foundation for students and helps them easily move to text-based programming later.

b) Game development

Used to create games with characters and game logic.
Users focus on gameplay ideas instead of complex coding.

c) Mobile App development

Used to develop Android and iOS apps.
Users design interfaces and app functions using visual blocks.

d) Robotics

Used to program robots like Micro:bit and Arduino UNO.
Students design robot movements, behaviors, and control sensors.

e) Web development

Used to create interactive websites.
Users define web elements and interactions using visual blocks.

f) Creative projects

Artists use block programming to make animations and interactive projects.
Popular platforms: Scratch, Blockly.

g) Modeling and simulation

Used to create models and simulations.
Users set different parameters and study system behavior easily.

h) Data science and visualization

Used to arrange data, perform analysis, and show results using charts and graphs.

Introduction to Scratch

Today’s world is full of technology and innovation. People use computers and digital devices for many tasks such as making documents, editing photos, playing games, and using creative tools like Photoshop.
Behind all these digital tools and games, the main magic is programming – giving instructions to the computer to perform different tasks.

Scratch is a popular and user-friendly block programming platform that helps beginners learn programming easily.

 About Scratch

• Scratch is a block-based programming language.

• It was developed by the Lifelong Kindergarten Group at MIT Media Lab.

• It is free and open-source software.

• Scratch has a large online community where users share projects.

• The current version is Scratch 3.0.

• Using Scratch, users can create:

  • Games

  • Animations

  • Interactive stories

  • Control robots and devices

Scratch looks fun but it also develops logic building and problem-solving skills like real programming.

 Downloading Scratch on PC (Offline)

Follow these steps:

1. Open a web browser and go to:
   https://scratch.mit.edu/download

2. Download the Scratch installer file.

3. Open the downloaded .exe file and install Scratch.

4. After installation, open the Scratch application and start creating projects.

 Using Scratch Online on PC

1. Go to: https://scratch.mit.edu

2. Click on Create to start a project.

3. To save or share projects, click Join Scratch and create an account.

4. Use the same details to log in later.

 Scratch for Mobile

Scratch also has a mobile app.

Steps:

1. Open your mobile app store.

2. Search for Scratch.

3. Download and install the app.

4. Open it and start making projects on your phone.

Features of Scratch

a) Drag and Drop Interface
You can create programs by joining blocks easily.

b) Event Driven
Programs respond to actions like clicking, pressing keys, or dragging.

c) Data and Variables
You can store and change data using variables.

d) Loops and Conditions
You can repeat actions and control program flow.

e) Sounds
You can add music and sound effects to your projects.

f) Community Sharing
Users can share their projects and explore others’ creations from around the world.

 Scratch Interface

Scratch has a colorful and user-friendly interface.
Both online and offline Scratch look the same.
The interface has four main parts:

1. Stage

2. Sprite

3. Blocks Palette

4. Scripts Area

Parts of Scratch Interface

a) Stage

The stage shows the output of your program.
Click the green flag to see your program run.

b) Sprite

Each object in Scratch is called a sprite.
By default, there is a cat sprite. You can change it using Choose a Sprite.

c) Blocks Palette

This area contains all the programming blocks.
Blocks are shown in different colors for different functions.

d) Scripts Area

You drag blocks here and connect them to make programs.

e) Extensions Library

This library adds extra features such as Music, Pen, micro:bit, etc.

f) Costumes Tab

Used to draw or edit the appearance of a sprite.

g) Sound Tab

Used to add sound effects or music to sprites.

h) Sprite Info Pane

Shows all sprites in your project.
Click on a sprite to select and program it.

i) File Tab

Used to open, save, or create new projects.

j) Choose a Sprite

Used to select new sprites from Scratch library.
Scratch has 339 built-in sprites.

k) Choose a Backdrop

Backdrop is the background image of the stage.
You can choose it from the Scratch library.

l) Project Name

Shows the name of your project.
Click it to rename your project.

m) Green Flag

This is the play button.
Click it to run your program.

n) Backpack

Used to store blocks and use them in other projects.

Concept of Block

Block programming uses colorful blocks to show commands or actions.
You make programs by dragging and dropping blocks and joining them together.

It is like playing with building blocks, but instead of making buildings, you make programs.

This type of programming is very easy for beginners.

 Example

To make a character move or jump, you just select the related blocks and connect them.
There is no need to type code.

 Benefits

• Easy to understand

• Helps develop creativity

• Improves problem-solving skills

• No syntax errors

 Assess Yourself Activity

1. Open Scratch.

2. Change the sprite from the cat to any other object.

3. Create a simple program using the Looks block:

   • Use the block say “Hello!”

   • Change the text to “Namaste!”

4. Click the green flag to see the result.

Components of Scratch

Scratch uses blocks as its main component.
Blocks are pre-programmed codes represented as colorful puzzle pieces that fit together.
There are 9 types of blocks in Scratch, each with a specific function to control the sprite’s behavior.

1. Motion Block

• Controls sprite movement: move, turn, point, or glide.

• Set or change sprite’s position, direction, or rotation style.

Example:

• turn 90 degrees combined with when clicked → sprite turns when clicked.

2. Looks Block

• Changes sprite’s appearance: costume, color, size, or visibility.

• Can make sprites say or think something.

Example:

• say “Namaste!” for 2 seconds combined with when clicked → sprite displays message.

3. Sound Block

• Plays, stops, or changes sound.

• Can play notes, drums, effects, or record sound.

Example:

• start sound Meow with when clicked → sprite makes a sound.

4. Events Block

• Triggers actions like:

  • when green flag clicked

  • when key pressed

  • when sprite clicked

Example:

• when sprite clicked → triggers actions assigned to that sprite.

 5. Control Block

• Controls the flow of the program: repeat, wait, stop.

• Use conditional statements: if, if-else, wait until.

Example:

• if <key space pressed?> then … else … → different actions based on condition.

6. Operators Block

• Performs math operations: add, subtract, multiply, divide, random numbers.

• Compare values: equal, greater, less, etc.

• Combine/manipulate text.

Example:

• 10 + 10 used in say block → displays calculation result.

7. Variables Block

• Create and use your own variables to store scores, names, levels, etc.

• Set, change, or show variable values.

Example:

• set myVariable to 0 combined with ask “What’s your name?” and wait → stores user input.

 8. My Blocks

• Create custom blocks for repeated or specific functions.

• Helps organize code and reuse blocks in projects.

Example:

• Create a block Add Two Numbers → can be used anywhere in the program.

 9. Sensing Block

• Detects user input, interactions, or environment.

• Can sense key presses, mouse position, sprite touching, or answer input.

Example:

• key space pressed? → triggers action when space key is pressed.

Lab / Activity Example: “Catch the Fruit Game”

1. Objective: Control a basket to catch falling fruits.

2. Steps:

   • Use motion blocks to move the basket left/right with arrow keys.

   • Use sprites for fruits falling from top.

   • Use event blocks for random fruit appearances.

   • Display score using variables and sensing blocks.

   • Add speed variations and sound effects for catching or missing fruits.

3. Save Project:

   • Online: Save to your account.

   • Offline: Save as .sb3 file.

Micro:bit and Arduino UNO 

History of Micro:bit

• BBC Micro:bit was developed in 2015 by the BBC in the UK.

• Aim: Encourage young people to learn coding and be creative digitally.

• Collaborators: BBC, ARM, Microsoft, and other educational partners.

• Designed to be simple, affordable, and practical for hands-on learning.

Components of Micro:bit

Micro:bit is a small physical computing device that combines hardware and software.

Component	Function
Microcontroller	Tiny computer that runs code on Micro:bit
5×5 LED Matrix	Display text, numbers, images, and animations
Sensors	Light and temperature sensors for real-world data
Buttons	Two buttons to trigger code
Microphone	Detect and send sounds or noises
Pin Connector	Connect wires or other hardware components
Physical Computing	Combines hardware & software to interact with real world

Quick Question:

• Microcontroller is a tiny computer ✅

Applications of Micro:bit

1. Education: Hands-on coding and electronics projects (games, gadgets)

2. Fitness: Step counters, workout trackers, fitness games

3. Games: Rock-paper-scissors, dice simulator, maze games

4. Fashion: Interactive garments and wearables with LEDs/sensors

5. Music: Create electronic instruments, compose beats, record sounds

6. Cooking: Digital timers, temperature sensors, recipe displays

7. Home & Garden: Smart home systems, automated watering, soil sensors

Fun Fact:

• Micro:bit can be controlled using Scratch through the Extensions tab.

Concept of Arduino UNO

• Arduino UNO is suitable for more advanced projects than Micro:bit.

• Widely used for LED flashlights, robotics, sensors, and data gathering.

• Name “UNO” comes from Italian/Spanish word for one.

History:

• Developed in 2010 by engineers David Cuartielles and Massimo Banzi

• Goal: Help students learn programming and electronics practically.

Components of Arduino UNO

Type	Components / Function
Hardware	Microcontroller (ATmega328P), 14 digital pins, 6 analog pins, USB port, power jack,         reset button, LED, crystal oscillator, voltage regulator
Software	Arduino IDE: write code and send to board, supports libraries for extra features

Tip: Tinkercad allows virtual Arduino projects and simulation using C, Python, or block programming.

Applications of Arduino UNO

1. Education: Teaching electronics and coding together

2. Home Automation: Lights, temperature, appliances

3. Robotics: Control motors, sensors, robotic vehicles

4. Wearable Tech: Digital watches, step counters

5. Data Gathering: Environment monitoring, GPS, motion detection

6. Gaming: Simple electronic games

7. Audio Projects: Music controllers, sound installations, interactive piano

8. Testing Products: Prototype electronic projects before hardware production

Key Difference:

• Micro:bit → Beginner-friendly, small projects

• Arduino UNO → Versatile, professional projects, more complex electronics

Python Exercise of Page no 240

 Input / Output

Q1. Write a program to ask input as “name” from the user and greet the user.

name = input("Enter your name: ")
print("Hello", name)

---

Q2. Write a program to input 3 sides of triangle and print area.

a = float(input("Enter side a: "))
b = float(input("Enter side b: "))
c = float(input("Enter side c: "))

s = (a + b + c) / 2
area = (s*(s-a)*(s-b)*(s-c)) ** 0.5
print("Area of triangle =", area)

---

Q3. Write a program to input a radius and find the area and circumference of circle.

r = float(input("Enter radius: "))
pi = 3.14

print("Area =", pi*r*r)
print("Circumference =", 2*pi*r)

---

Q4. Write a program to input 3 digits and calculate sum and average.

a = int(input("Enter first number: "))
b = int(input("Enter second number: "))
c = int(input("Enter third number: "))

sum = a+b+c
avg = sum/3

print("Sum =", sum)
print("Average =", avg)

---

Q5. Write a program to input diameter and print area and circumference of circle.

d = float(input("Enter diameter: "))
r = d/2
pi = 3.14

print("Area =", pi*r*r)
print("Circumference =", 2*pi*r)

---

 Constant Value & Operators

Q6. Show arithmetic operators.

a = int(input("Enter a: "))
b = int(input("Enter b: "))

print("Add =", a+b)
print("Subtract =", a-b)
print("Multiply =", a*b)
print("Divide =", a/b)
print("Square of a =", a*a)
print("Modulus =", a%b)

---

Q7. Show comparison operators.

a = int(input("Enter a: "))
b = int(input("Enter b: "))

print(a==b)
print(a<=b)
print(a>=b)
print(a!=b)

---

If – Else

Q8. Check positive number.

n=int(input("Enter number: "))
if n>0:
    print("Positive")

---

Q9. Voting eligibility.

age=int(input("Enter age: "))
if age>=18:
    print("Eligible")
else:
    print("Not eligible")

---

Q10. Even or odd.

n=int(input())
if n%2==0:
    print("Even")
else:
    print("Odd")

---

Q11. Smallest of two numbers.

a=int(input())
b=int(input())

if a<b:
    print(a,"is smallest")
else:
    print(b,"is smallest")

---

Q12. Pass or Fail.

m=int(input("Enter marks: "))
if m>=40:
    print("Pass")
else:
    print("Fail")

---

Q13. Traffic light program.

c=input("Enter color: ")

if c=="green":
    print("Go")
elif c=="red":
    print("Stop")
elif c=="orange":
    print("Be Ready")
else:
    print("Invalid color")

For Loop

Q14. Print 1–15.

for i in range(1,16):
    print(i)

---

Q15. Print name 20 times.

name=input("Enter name: ")
for i in range(20):
    print(name)

---

Q16. Squares 1–5.

for i in range(1,6):
    print(i*i)

---

While Loop

Q17. Factorial.

n=int(input())
f=1
while n>0:
    f*=n
    n-=1
print("Factorial =",f)

---

Lists

Q18. Create list and print.

lst=[1,2,3,4,5]
print(lst)

---

Q19. List of squares 1–10.

s=[i*i for i in range(1,11)]
print(s)

---

Dictionaries

Q20. Create dictionary.

d={"a":1,"b":2,"c":3}
print(d)

---

Q21. Check key exists.

print("a" in d)