Class 11 Informatics Practices – Ch 1. Computer System NCERT Solution

Class 11 Informatics Practics

Chapter 1: Computer Systems – NCERT Exercise Solution


  • A computing device, also referred as computer processes the input data as per given instructions to generate desired output.
  • Computer processes data to generate information whose further analysis and interpretation yields knowledge.
  • Computer system has four physical components viz. i) CPU ii) Primary memory iii) Input device and iv) Output device. They are referred to as hardware of computer.
  • Computer system has two types of primary memories viz. i) RAM the volatile memory and ii) ROM the non-volatile memory.
  • Software is a set of instructions written to achieve the desired task and are mainly categorised as system software, programming tools and application software.
  • Hardware of a computer cannot function on its own. It needs software to be operational or functional.
  • Operating system is an interface between the user and the computer and supervises the working of computer system i.e. it monitors and controls the hardware and software of the computer system.

Class 11 Informatics Practices Chapter 1: Computer Systems – NCERT Exercise Solution

Exercise with Solutions

Question 1: Name the software required to make a computer functional. Write down its two primary functions.

Answer: Operating System – An operating system is a system software, which provide interface between user and hardware.

Two Primary functions of Operating systems are –

  • Process Management
  • File Management
  • Storage Management
  • Print Management
  • Service Management
  • Security

Question 2: What is the need of RAM? How does it differ from ROM?

Answer: RAM stands for Random Access Memory. RAM is a primary memory, which is an essential component of computer system. Programs and data are loaded into the primary memory before processing. CPU directly interacts with the primary memory (RAM) to perform read / write operation.

Difference between RAM and ROM

  1. RAM is a volatile memory while ROM is a non-volatile memory.
  2. RAM is used to store data temporarily while computer is working. OS loads all necessary programs and data into RAM, while ROM is a permanent storage, it keep the BIOS information which helps in starting of computer.
  3. RAM allows both READ and WRITE operations, while ROM allows only READ operation (READ Only).

Question 3: What is the need for secondary memory?

Answer: Primary memory has limited storage capacity and is either volatile (RAM) or read-only (ROM).

Thus, a computer system needs auxiliary or secondary memory (storage) to permanently store data and instructions for future use.

The secondary memory is non-volatile and has larger storage capacity than primary memory. It is slower and cheaper than the main memory. But, it cannot be accessed directly by the CPU. Contents of secondary storage need to be first brought into the main memory for the CPU to access. Examples of secondary memory devices include Hard Disk Drive (HDD), CD/ DVD, Memory Card, SSD, etc.

Question 4: Draw the block diagram of a computer system. Briefly write about the functionality of each component.

Answer: Block Diagram of Computer System is –

Input Unit(Device) :-  Input Unit (device) is use to send the data and instruction to the Computer System i.e. CPU. Generally Inputted data and instructions are stored in primary memory. Input unit convert the input data into a digital form that is understand by computer system.

Output Unit (Device) :- The device that receives data from a computer system for display, physical production i.e. print out, called output unit. Output unit receive the data in digital form which it convert into the human understandable form.

Central Processing Unit: CPU is the brain of computer system, which perform all processing task. Microprocessor is the main component of CPU, which perform all types of processing. CPU is divided into three sub units – Control Unit, Arithmetic and Logic Unit and Primary Memory.

Control Unit – It controls all the other units. Control unit send the control signals to all unit whenever it is required.

Arithmetic and Logic Unit – ALU perform arithmetical and logical calculations. Arithmetic means Addition, subtraction, multiplication and division. Logical means comparison like greater than, less than etc.

Primary Memory – Primary memory mainly use to store the working data and instructions.

Secondary Storage – Secondary storage is permanent storage, which is used to store the data and software permanently for future use.

Question 5: Differentiate between proprietary software and freeware software. Name two software of each type.

Answer: Proprietary software is a software, which license we need to purchase from vendor while freeware software is freely available, we can download it from internet.


Proprietary Software – Windows 10, Microsoft Office, Tally, Adobe Photoshop

Freeware – Ubuntu, LibreOffice Writer, Mozilla Firefox

Question 6: Mention any browsers used for browsing the internet.

Answer : Google Chrome, Mozilla Firebox, Microsoft Edge, Opera, Safari etc.

Question 7: Name the input/output device used to do the following:

To output audio

To enter textual data

To make hard copy of a text file

To display the data or information

To enter audio-based command

To build 3D models

To assist a visually impaired individual in entering data


To output audio                             –       Speaker

To enter textual data                     –       Keyboard

To make hard copy of a text file      –       Printer

To display the data or information   –       Monitor or Projector

To enter audio-based command      –       Mic

To build 3D models                        –       3 D Printer

To assist a visually impaired individual in entering data – Brail Keyboard

Question 8: Identify the category (system, application, programming tool) of the following software:




Text editor

Answer : a.     Compiler           –       Programming Tools

        b.     Assembler         –       Programming Tools

        c.      Ubuntu              –       System Software

        d.     Text Editor        –       Programming Tools /Application Software

Class 11 Informatics Practices – Chapter 1: Computer Science NCERT Book Exercise Solution

Question 9: Convert the following into bytes:

(a) 2 MB

(b) 3.7 GB

(c) 1.2 TB

Answer:   (a). 2MB => 2,000,000

(b). 3.7GB => 462,500,000

(c). 1.2TB => 150000000000

Question 10: What is the security threats involved when we throw away electronic gadgets that are non-functional?

Answer: Security threat can increase if the electronics and magnetic stripped cards are not disposed without a proper disposing process {like cutting the cards before throwing it}. The hackers can advantage of this and can use these gadgets to hack anyone easily.

Question 11: Write down the type of memory needed to do the following:

To store data permanently

To execute the program

To store the instructions which cannot be overwritten.

Answer:  a) To store data permanently => Secondary

b) To execute the program => RAM

c) To store the instructions which cannot be overwritten => ROM

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Class 11 Informatics Practices – NCERT Exercise Solution

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Class 12 Informatics Practices – NCERT Exercise Solution

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