Class 12 English Notes | Class 12 English All Chapter Exercise

1. Write the full forms of the following abbreviations.

i. EC – Electronic Communication
ii. MHz – Megahertz
iii. GHz – Gigahertz
iv. ms – Millisecond
v. ns – Nanosecond
vi. Ps – Picosecond
vii. Fs – Femtosecond
viii. GIGO – Garbage In Garbage Out
ix. RAM – Random Access Memory
x. IPOS – Input Process Output Storage
xi. ATM – Automated Teller Machine
xii. CT Scans – Computed Tomography Scans

2. Choose the correct answer.

    a. Which fraction of a second is equivalent to one millionth of a second?
        i) Milliseconds
        ii) Microsecond
        iii) Nanosecond
        iv) picoseconds

    b. Incorrect input results in incorrect output. It is referred to as ….
        i) FIFO
        ii) LIFO
        iii) GIGO
        iv) None of the above

    c. How many kilobytes are in one megabyte?
        i) 1030
        ii) 1000
        iii) 1048
        iv) 1024

    d. Repeatedly working capability of computers is known as ………..
        i) storage
        ii) speed
        iii) diligence
        iv) versatility

    e. What is the primary function of the CPU in a computer system?
        i) Memory storage
        ii) Data input
        iii) Arithmetic and logic operations
        iv) Graphics rendering

 3. Write short answers to these questions.

a) Define the Computer.
Ans. A computer is an electronic machine that takes input, processes it, and gives output. It works very fast and stores data for future use.

b) How do IPOS work?
Ans. IPOS stands for Input, Process, Output, and Storage.

• Input: Data is entered into the computer.
• Process: The computer processes the data using programs.
• Output: The result is shown on screen or printed.
• Storage: Data and results are saved for future use.

c) What is GIGO?
Ans. GIGO means Garbage In, Garbage Out. If wrong or bad data is entered into the computer, the output will also be wrong.

d) List any four computer features.

Ans. The four computer features are:

1. Speed
2. Accuracy
3. Storage
4. Versatility

e) Why is a computer called a diligence machine?
Ans. A computer is called a diligence machine because it never gets tired or bored and can work continuously without losing accuracy.

f) List four computer-related uses.

Ans. The four computer related uses are:

1. Education
2. Banking
3. Communication
4. Entertainment

g) Identify distinct computer storage units.

Ans. The Identified distinct computer storage units are:

1. Bit
2. Byte
3. Kilobyte (KB)
4. Megabyte (MB)
5. Gigabyte (GB)
6. Terabyte (TB)

4. Write long answers to these questions.

a) Explain the working principles of computers with a block diagram and explain it in detail.

Ans. A computer is an electronic device that processes data according to instructions provided by software programs. It operates by taking input, processing it, storing data as needed, and producing output. Below, I’ll explain the working principles of a computer, provide a block diagram, and describe each component in detail.

Block Diagram of a Computer

   +-----------------+

   |    Input Unit   |<---- Input Devices (Keyboard, Mouse, etc.)

   +-----------------+

            |

            v

   +-----------------+

   | Central         |

   | Processing Unit |<----> +-----------------+

   | (CPU)           |      | Memory Unit     |

   | - ALU           |      | - Primary (RAM) |

   | - Control Unit  |      | - Secondary     |

   +-----------------+      |   (HDD, SSD)    |

            |               +-----------------+

            v

   +-----------------+

   |   Output Unit  |----> Output Devices (Monitor, Printer, etc.)

   +-----------------+

Working Principles of a Computer

Ans. The computer operates based on the Input-Process-Storage-Output cycle:

1. Input: Data and instructions are fed into the computer via input devices.

2. Process: The CPU processes the input data by performing computations and logical operations.

3. Storage: Data and instructions are stored in memory for immediate or future use.

4. Output: Processed data is presented to the user through output devices.

Detailed Explanation of Each Component

1. Input Unit:

   - Function: Accepts data and instructions from the user or external sources.

   - Examples: Keyboard, mouse, scanner, microphone, webcam.

   - How it Works:

     - Input devices convert user actions (e.g., typing, clicking) into digital signals the computer understands.

     - For example, a keyboard sends binary codes corresponding to pressed keys to the CPU.

   - Role in the System: Acts as the interface between the user and the computer, enabling data entry.

2. Central Processing Unit (CPU):

   - Often called the "brain" of the computer, the CPU is responsible for executing instructions.

   - Subcomponents:

     - Arithmetic Logic Unit (ALU):

       - Performs arithmetic operations (addition, subtraction, etc.) and logical operations (comparisons like AND, OR, NOT).

       - Example: If a program requires adding two numbers, the ALU handles the computation.

     - Control Unit (CU):

       - Directs the operation of the processor by fetching instructions from memory, decoding them, and coordinating their execution.

       - It controls data flow between the CPU, memory, and input/output devices.

     - Registers:

       - Small, high-speed storage areas within the CPU for temporary data during processing (e.g., instruction register, program counter).

   - How it Works:

     - The CPU follows the Fetch-Decode-Execute cycle:

       1. Fetch: Retrieves an instruction from memory.

       2. Decode: Interprets the instruction to determine the required action.

       3. Execute: Performs the instruction (e.g., computation or data transfer).

     - The CPU interacts with memory and I/O devices to complete tasks.

3. Memory Unit:

   - Stores data and instructions for processing.

   - Types:

     - Primary Memory (RAM):

       - Volatile, temporary storage used for data and instructions the CPU needs immediately.

       - Example: When you open a program, it’s loaded into RAM for quick access.

       - Fast but limited in capacity and loses data when power is off.

     - Secondary Memory (HDD, SSD):

       - Non-volatile, permanent storage for data and programs.

       - Example: Hard drives or solid-state drives store operating systems, files, and applications.

       - Slower than RAM but offers larger capacity.

     - Cache Memory:

       - High-speed memory between the CPU and RAM to store frequently accessed data, improving processing speed.

   - How it Works:

     - The CPU retrieves data/instructions from memory, processes them, and stores results back in memory if needed.

4. Output Unit:

   - Function: Presents processed data to the user in a usable form.

   - Examples: Monitor, printer, speakers.

   - How it Works:

     - Converts processed digital data into human-readable or usable formats (e.g., text/images on a screen, printed documents).

     - Example: A monitor displays the results of a calculation performed by the CPU.

   - Role in the System: Communicates the results of processing to the user.

b) Describe the use of computers in the education field.

Ans. Computers have transformed education by enhancing teaching, learning, and administration. Below is a concise description of their uses in the education field:

1. Enhanced Learning:

   - E-Learning Platforms: Computers enable access to online courses (e.g., Coursera, Khan Academy), allowing students to learn at their own pace.

   - Interactive Tools: Software like simulations, educational games, and virtual labs (e.g., PhET simulations) make complex subjects engaging and interactive.

   - Access to Resources: Students use computers to access digital libraries, research databases (e.g., Google Scholar), and educational videos.

2. Teaching and Instruction:

   - Digital Classrooms: Teachers use computers for presentations, interactive whiteboards, and multimedia to deliver lessons.

   - Learning Management Systems (LMS): Platforms like Moodle or Google Classroom help teachers share materials, assign tasks, and track progress.

   - Personalized Learning: Adaptive software tailors content to individual student needs (e.g., Duolingo for language learning). 

3. Administrative Efficiency:

   - Record Keeping: Computers manage student records, grades, and attendance through software like PowerSchool.

   - Communication: Email and platforms like Zoom facilitate parent-teacher meetings and remote classes.

   - Timetabling: Software automates scheduling for classes and exams. 

4. Skill Development:

   - Digital Literacy: Students learn coding, data analysis, and software use (e.g., Python, Microsoft Office), preparing them for modern careers.

   - Collaboration: Tools like Google Docs enable group projects and real-time collaboration.

5. Accessibility and Inclusion:

   - Special Needs Support: Assistive technologies (e.g., text-to-speech, screen readers) aid students with disabilities.

   - Remote Learning: Computers enable education for students in remote areas via online classes.

6. Research and Innovation:

   - Data Analysis: Computers help researchers and students analyze data using tools like SPSS or Excel.

   - Virtual Reality (VR): VR applications create immersive learning experiences, such as virtual field trips.

Impact: Computers make education more accessible, interactive, and efficient, enabling personalized learning, global connectivity, and skill development for the digital age.