Class-XI (Computer Science-NCERT)

Chapter-1: Computer System

A computer system composed of a central processing unit (CPU), memory, input/output devices, and storage devices. All these components work together as a unit to deliver the desired output.

Q[1]: Name the software required to make a computer functional. Write down its two primary services.

Ans: Name of the Software: – Operating System

Primary services: –

• Process management
• File management

Q[2]: How does the computer understand a program written in high level language? [Class-XI Computer Science-NCERT]

Ans: As we know computer understand instruction in machine code. A translator such as compiler is used to convert high level language to machine code.

Q[3]: Why is the execution time of the machine code less than that of source code? [Class-XI Computer Science-NCERT]

Ans:

Machine code consists of 0s and 1s which are directly understood and executed by the
computer.

Q[4]: What is the need of RAM? How does it differ from ROM?

Ans:

RAM (main memory): Data entered through input device is temporarily stored in the RAM where user can perform both read and write operations. It is a Volatile Memory.

ROM (Read Only Memory): it is used to store system’s instructions permanently. It allows read operation only. it does not allow to write operation. It is a non-volatile Memory.

Q[5]: What is the need for secondary memory?

Ans: The secondary memory is used to store the large amount of data for long time. It is a non-volatile and has larger storage capacity than primary memory.

Q[6]: How do different components of the computer communicate with each other?

Ans: Bus is used to transfer the data between components. There are three types of bus: –

• Data bus to transfer data between different components.
• Address bus to transfer addresses between CPU and main memory.
• Control bus to communicate control signals between different components of a computer.

Q[7]: Draw the block diagram of a computer system. Briefly write about the functionality of each component.

• ALU performs all the arithmetic and logic operations as per the instruction in a program.
• CU controls sequential instruction execution interprets instructions and guides data flow through the computer’s memory.
• Input device sent data into a digital form that is acceptable by the computer system.
• Output device is used to display or print information.
• Primary memory (RAM) is used to store the data entered through input device is temporarily.
• Secondary storage is permanent storage device used to store the data for future use.

Q[8]: What is the primary role of system bus? Why is data bus being bidirectional while address bus is unidirectional?

ANs: As the CPU may require reading data from main memory or write data to main memory, a data bus is bidirectional.

Q[9]: Differentiate between proprietary software and freeware software. Name two software for each type. [Chapter-1 Computer System]

Ans:

A software purchased from the vendor who has the copyright of the software is a proprietary software. For example: Windows OS, Tally. A Freeware software is available at free of cost to use, but source code may not be available. For Example: Skype, Adobe Reader

Q[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:

Microcontroller is a small computing device which has a CPU, RAM, ROM and other peripherals embedded on a single chip.

A microprocessor is a small-sized electronic component inside a computer that performs basic arithmetic and logical operations on data.

Smart home appliances have a microcontroller because it is smaller in size, less costly and consumes less power which performs multiple tasks. it is directly operated by using simple control functions and commands.

Q[11]: Mention the different types of data that you deal with while browsing the Internet.

Ans:

• Structured data.
• Unstructured data.
• Semi-structured data.

Q[12]: Categories the following data as structured, semi structured and unstructured:

Ans:

• Newspaper: Unstructured
• Cricket Match Score: Semi-structured
• HTML Page: Semi-structured
• Patient records in a hospital: Structured

Q[13]: Name the input or output device used to do the following: [Chapter-1 Computer System]

Ans:
a) To output audio. Ans: – Speaker
b) To enter textual data. Ans: – keyboard
c) To make hard copy of a text file. Ans: – Printer
d) To display the data or information. Ans: – Monitor/ Display Unit
e) To enter audio-based command. Ans: – Mic
f) To build 3D models. Ans: -3D printers and 3D Scanners
g) To assist a visually impaired individual in entering data. Ans: – Braille keyboards

Q[14]: Identify the category (system, application, programming tool) of the following software:

a) Compiler. Ans: programming tool software
b) Assembler. Ans: programming tool software
c) Ubuntu. Ans: System software
d) Text editor. Ans: Application software