Chapter 1 : Computer System | class 11th | Ncert solution for computer

NCERT Solution Class 11 Computer Science Chapter 1 – Computer System

1.) Name the software required to make a computer functional. Write down its two primary services?

Ans: To make a computer functional operating system is required. The two services of primary services:

1) Operating system provides services for building and running the application.

2) Operating system provide user interface to the user for enable interaction between computer and  user.

2.) How does the computer understand a program written in high level language?

Ans: Computer understands only machine level language (0 and 1). High level language is a simple English type language written in some symmetric format. To convert high level language into machine language there is need of compiler which can be understood by computer.

3.) Why is the execution time of the machine code less than that of source code?

Ans: We know that computer readable language is machine language. So there is no need to convert machine language whereas Source codes are written in high level language. So there is need to convert it into machine language first. Hence, the execution time of machine language is less than source code.

4.) What is the need of RAM? How does it differ from ROM?

Ans:  RAM (random access memory) is used for quickly accessing a data. RAM is a temporary storage memory and it stores the active using data. Whereas ROM is a read only memory and it is a permanent storage device. Data in RAM is erased when power goes off whereas in ROM data remain as it is.

5.) What is the need for secondary memory?

Ans:  Secondary memory provides a large storage facility as well as it is very cheap .There is a need of secondary storage because it is a permanent storage device. Unlike ROM and RAM secondary memory doesn’t have limited storage.

6.) How do different components of the computer communicate with each other?

Ans: Component of a computer communicate with each other with the help of system bus. System bus provides the facility to transfer the data as well as memory address between one component to another.

7.) Draw the block diagram of a computer system. Briefly write about the functionality of each component.

Ans:

INPUT UNIT :

Input unit has following function:

• Input unit takes a data instruction from the user for further processing.
• We know that computer understand machine language. Input unit converts the data to the machine language (machine readable form)

They are various types of input devices are available like keyboard, scanner, mouse, touch screen devices, etc.

CENTRAL PROCESSING UNIT:

CPU i.e.  Central processing unit is responsible for performing all tasks of computer. CPU is like a heart of computer.CPU consists of 3 units:

• Primary memory
• Control unit
• Arithmetic logic unit

ALU:

Arithmetic and logical unit responsible for performing all arithmetic operation like addition, subtraction, multiplication and division .It also responsible for conduct merging, sorting like all sorting techniques .All the calculations of the data perform by ALU.

Control unit:

Control unit is used to control the signals. Control unit receives the instruction, data, and information from input devices and converts it into control signals.

Primary memory:

There are two types of primary memory

• RAM
• ROM

RAM:

• RAM means random access memory.
• It is a volatile storage.
• The data stored in RAM temporary.
• RAM stores the data of active task.

 ROM :

• ROM mans read only memory.
• The data stored in ROM is permanent.
• It cannot be erased during the power cut off.
• It is a non volatile memory.

OUTPUT UNIT:

An output device is one of the components of computer. output devices is responsible to convert machine code into the human readable form. Monitor, printer etc. are output devices.  The output given by the computer can be in any type like text, graphics, audio, video etc

8.) What is the primary role of system bus? Why data bus is is bidirectional while address bus is unidirectional?

Ans :  To transfer the data, address, control signal between the computer there is a need of system bus. With the help of system bus components of a computer can communicate with each other. Data bus is bidirectional because of two-way transfer process. IT transfers the data among CPU,memory and other peripheral devices. Address bus is unidirectional because whenever the data written in the memory, CPU placed the data on data bus. After that address bus provide specific address to   write the data.

9.) Differentiate between proprietary software and freeware software. Name two software for each type.

Ans:

Proprietary software	Freeware software
Proprietary software is software which is not available freely or publically.	Freeware software are available anywhere publically.
To get Proprietary software there is a need of authenticate license	To get freeware software there is no need of authenticate license
To get Proprietary software we must have to pay for it	free software are free of charge
Example: adobe flash player, winRAR	Example: Linux, vlc player

10.) Write the main difference between microcontroller Notes and microprocessor. Why do smart home appliances have a microcontroller instead of microprocessor embedded in them?

Ans:

MICRO CONTROLLER	MICRO PROCESSOR
Micro controller used for perform particular task	Micro processor used for intensive processing
Micro controller does not  have capacity to perform multiple  task	Micro processor have capacity to perform multiple  task
Size of micro controller: 8bit,16 bit,32 bit	Size of micro processor: 64 bit,32 bit
Micro controller is cheaper in cost	Micro processor is expensive
MICRO CONTROLLER consumed less power	MICRO processor consumed more power
Application: microwave oven	Application: computer, laptop

Smart home appliances have a micro controller because it consumed less electricity. As well as it is very low in cost. Microcontroller requires very less space, it does not require CPU and other peripheral devices.

11.) Mention the different types of data that you deal with while browsing the Internet.

Ans:

Different types of data while browsing the Internet:

Structured: the data which is stored in most organized way is known as structured data

Unstructured: the data which is not stored in organized way is known as unstructured data

Semi structured: the data lies in between the structured and unstructured data is known as semi structured data

12.) Categories the following data as structured, semi structured and unstructured:

• Newspaper
• Cricket Match Score
• HTML Page
• Patient records in a hospital

Ans:

STRUCTURED	SEMI STRUCTURED	UNSTRUCTURED
Patient record in hospitalCricket match score	Html page	newspaper

13.) Name the input or output device used to do the following:

a) To output audio

b) To enter textual data

c) To make hard copy of a text file

d) To display the data or information

e) To enter audio-based command

f) To build 3D models

g) To assist a visually-impaired individual in entering data

Ans:

a) To output audio – Speaker

b) To enter textual data – Keyboard

c) To make hard copy of a text file – Printer

d) To display the data or information – Monitor

e) To enter audio-based command – Mic

f) To build 3D models – 3D Printer

g) To assist a visually-impaired individual in entering data – Braille keyboards

14.) Identify the category (system, application, programming tool) of the following software:

a) Compiler

b) Assembler

c) Ubuntu

d) Text editor

Ans:

a) Compiler – Programming tool

b) Assembler – Programming tool

c) Ubuntu – System

d) Text editor – Application