Bishop Cotton School, Shimla

Computer Science

Class 7

Study Material

(1st April to 14th April, 2020)

General Instructions

The study material contains four components:

Chapter 1(Answers for Back Exercises)

Chapter 1 Notes

Question Bank(chapter 1)

Practical Activity

Chapter 1 (Solution): The first component contains solution for the back exercises (Chapter 1).

Please ensure all the questions and answers are written in the computer notebook. (Please

don’t rewrite if the work has already been completed in the notebook.)

Chapter 1 Notes: Students must read the notes thoroughly for better understanding of the

chapter.

Question Bank (chapter 1): Question bank contains some questions related to the chapter.

Students are not required to submit any hardcopy /hand written copy of the answers for the

question bank to the teacher. Students should make use of these questions for self

assessment. Parents may use these questions for testing the learning outcome of the

students. Parents and students may apply any method/technique for revision as per the

available resources. Answer key is also provided.

Practical Activity: Designing a time table in MS EXCEL.

For Any other queries regarding the computer assignment, please contact via email

ankitadogra.official@gmail.com

Chapter 1

Computer - Hardware components

(Solution)

EXERCISES (Section A)

A. Quiz

1. Modem stands for what?

Answer

Modem stands for modulator and demodulator

2. Where is Motherboard located?

Answer

Motherboard is located at the backside of the CPU cabinet.

B. Fill in the blanks.

1. The physical components of a computer which we can touch and feel are known

as hardware.

2. A motherboard is also known as main board.

3. A sound card is also known as audio card.

4. The main secondary storage device inside the CPU is called primary memory.

C. State True or False.

1. A video card is an expansion card. True

2. Projector displays video, images on a smaller screen. False

3. Digital camera is used to take photographs. True

4. Parallel port sends multiple bits of data at one time. True

5. USB stands for Universal Sequential Bus. False

D. Multiple Choice Questions.

Tick the correct option.

1. Inkjet printer forms letters and images on the paper.

2. Microphone sends voice signals to a computer.

3. Flash drive is also known as pen drive.

Section B

A. Answer the following.

1. Explain the types of printers.

Answer

The three types of printers are:

Dot Matrix Printer

It contains a movable print head with pins that strike the ribbon placing a dot on

the paper with hundreds of dots forming images or text.

The speed of this printer is given in CPS (Character per second).

Inkjet printer

It forms letters and images on the paper by spraying small streams of quick

drying ink.

The speed of this printer is given in LPM (line per minute)

Laser printer

It uses laser technology to print images on the paper.

The speed of this printer is given in PPM (pages per minute)

2. What is modem?

Answer

Modem stands for modulator and demodulator. It is mainly used to connect

communication line with the computer system for data transfer. The function of

this device is to convert digital signals to analog and vice versa.

3. What is motherboard? What does it contain?

Answer

Motherboard is one of the essential components of computer system which

provides connectivity to various parts of the computer system so that they can

communicate with each other.

The components like CPU, RAM and ROM are plugged to it whereas the devices

like the keyboard, mouse and hard disk are connected with the help of sockets

and slots available on it.

4. Write short note on SMPS.

Answer

SMPS is an electronic power supply which transfers electric power from a source

(AC) to a low voltage (DC).

SMPS is required for the working of various components of a computer system.

It ensures that proper power supply is available for the working of computer

system.

5. Explain the two types of mouse.

Answer

(Any TWO out of four)

Mechanical Mouse

It has a rubber ball which spins in all directions.

The free movement of the ball on the flat surface moves the pointer on the

monitor screen.

Wireless Mouse

It provides connectivity without wire or cable.

The transmitter in mouse sends electromagnetic signals to the computer for

detection of clicks and movements.

Trackball mouse

It makes use of a socket fixed with sensors.

The sensor tracks the movement of the ball to move the mouse pointer on the

screen.

Optical Mouse

It uses optical sensors.

Laser technology is used to track the movement of the mouse pointer.

They have more precision and speed as compared to the mechanical mouse.

6. Name the types of port.

Answer

The different types of ports are:

Serial Port

Parallel Port

PS2 Port

USB Port

VGA Port

B. Computer in Everyday Life(Application Based questions)

1. Simran drew a picture and gave the print command. Which software has she

used to draw the picture? Name the device she has used to take the output.

Answer

Simran used Paint application.

She used printer to take the output.

2. Nisha wants to work with software which requires more memory than her

computer has. Her computer is not able to run the software properly. What

should she do?

Answer

Nisha should add more RAM to the system.

Chapter 1

Hardware components

(Notes)

Computer: It is an electronic device used to take input, process data and display the result.

IPO CYCLE

Computer follows the IPO cycle. It takes input from the user, processes the data and gives

information as the output.

INPUT->Processing->OUTPUT

Computer has two main components

Hardware

Software

Hardware: Hardware is the physical component of the computer that you can touch and see.

Software: Software is a set of programs that controls the functioning of computer hardware.

Software is classified into two types:

System software

Application Software

Types of hardware:

Internal hardware

External hardware

Internal hardware: Internal components are the devices that are fixed to the

motherboard or attached to the motherboard inside a CPU.

External hardware: External components are the physical devices which are externally

connected to the computer.

INTERNAL HARDWARE

• Motherboard

It is a main circuit board that allows communication between the different

components of the computer.

The components like CPU, RAM and ROM are directly plugged to the motherboard.

It is located at the backside of CPU.

• SMPS (Switched Mode Power Supply)

Switched Mode power supply provides power supply to the components of the

computer.

It is the electronic power supply which transfers power from a source (AC) to low

voltage (DC).

It ensures that proper power supply is available for the working of the computer

system.

PCI

Peripheral Component Interconnect is an interface for connecting various

peripheral devices with the main board of the computer system.

In earlier computers, PCI slots were present on the motherboard but in the latest

computers these cards are either integrated on the motherboard or connected

using USB or PCI express.

Sound Card

It is also known as the audio card.

It is an expansion card which is used for working with sound signals.

It helps to connect devices like the speaker and microphone.

It converts the digital signals to sound signals and vice versa.

Video Card

It is also known as the graphics card.

It is an expansion card used to enhance the video quality of the graphics

signals.

It sends graphical information to the visual display unit like monitor,

projectors, etc.

• Ports: Port acts an interface used to connect different peripheral devices like

keyboards, mouse, monitors, etc.

Types of ports:

a. Serial port

It supplies data serially i.e. bit by bit.

It is also known as the COM port.

It is slow as compared to parallel port.

It generally consists of 9 pins.

It is used to connect devices like mouse, modem, etc.

b. Parallel port

It supplies multiple bits at a time.

It is fast as compared to serial port.

It generally consists of 24 pins.

It is used for connecting devices with high bandwidth.

It is used for connecting devices like printers.

c. PS/2 port

It was used by the IBM supported devices.

It usually consists of 6 pinholes.

It is used for connecting keyboard and mouse.

d. USB port

USB stands for Universal Serial Bus.

USB uses the latest technology which transfers data as well as

provide power to the connected devices.

It is a versatile port used for connecting printers, plotters,

mouse, keyboards etc.

e. VGA port

Video Graphics Array port is used to transfer analog video

signals from PC to video device.

It is used to connect video output devices like monitors or

projectors.

MODEM

It stands for modulator and demodulator.

It is used to connect the communication line with the computer system for

data transfer.

The function of this device is to convert digital to analog and vice versa.

Modulation means converting digital to analog signal.

Demodulation means converting analog to digital signal.

Types of modem: Internal and External modem

CPU

It stands for central processing unit.

It is responsible for processing in the computer system.

It is also known as the brain of the computer system.

CPU is responsible for all calculations and controlling the operations of the

other units of the computer system.

CPU

INPUT

SECONDARY MEMORY

OUTPUT

PRIMARY MEMORY

CU ALU

Components of CPU:

o ALU: It stands for Arithmetic logic unit. It is used for arithmetic and logical

operations.

o MU: It stands for Memory Unit. It is the temporary storage which receives

data, holds it and delivers it according to the information.

o CU: It stands for Control Unit. It is used to control the peripherals. It takes data

to the ALU, and from ALU to memory, and then to the output device.

Memory Unit

Memory unit is the basic unit to store data.

Primary memory is divided into two types: RAM and ROM

RAM

o It stands for Random Access Memory.

o It is the temporary memory.

o It is also known as scratch pad.

o RAM is expensive.

o Types of RAM- Static RAM and Dynamic RAM

o Static RAM keeps the data till the power is switched off.

o Dynamic RAM refreshes itself continuously in order to maintain data.

ROM

o It stands for Read only memory.

o It is a permanent memory.

o It is used to store manufacturer’s instructions.

o ROM stores the initial program called the Bootstrap Loader that contains

the instruction to load the operating system.

o Types of ROM –

o PROM: It stands for Programmable Read Only Memory. This type of

ROM can be programmed once but PROM chip cannot be altered or

erased.

o EPROM: It stands for Erasable Programmable Read Only Memory. It

is also known as UVEPROM (Ultra violet EPROM).This type of ROM

allows user to reprogram the ROM using UV rays.

o EEPROM: It stands for Electrically Erasable Programmable Read Only

Memory. This type of ROM can be reprogrammed. Its contents can

be erased electrically.

Heat Sink

Heat Sink is an electronic device which is used to cool the central

processing device.

Types of heat sink

Passive heat sink – It uses the aluminum radiator which dispatches

the heat through convection.

Active sink- It uses a fan to cool down the room temperature.

Disk Drive

It is a part of computer system which is used for storing or retrieving data

on a storage device.

These drives use different technologies for storing data.

CD’s use the laser technology for storing data.

Hard disk drive uses magnetic technology for storing information.

EXTERNAL HARDWARE

It is of three types:

Input devices

Output devices

External storage devices

1. Input devices: It is used to feed data into the computer system. Example-keyboard,

mouse, joystick, light pen, scanner.

Keyboard

It is used to enter data and give instructions to the computer.

It has many buttons called keys.

A standard keyboard has 104 keys.

Mouse

Mouse is used to move the pointer on the screen.

It works on the principle of point and click.

It is used to point the objects on the screen and the buttons help in selecting

the objects.

Types of Mouse

o Mechanical Mouse

It has a rubber ball which spins in all directions.

The free movement of the ball on the flat surface moves the

pointer on the monitor screen.

o Wireless Mouse

It provides connectivity without wire or cable.

The transmitter in mouse sends electromagnetic signals to

the computer for detection of clicks and movements.

o Trackball mouse

It makes use of a socket fixed with sensors.

The sensor tracks the movement of the ball to move the

mouse pointer on the screen.

o Optical Mouse

It uses optical sensors.

Laser technology is used to track the movement of the

mouse pointer.

They have more precision and speed as compared to the

mechanical mouse.

Scanner

o It is used to scan images, posters, magazines directly into the computer.

o Types of scanners

Flatbed Scanner: The object to be scanned is placed on a flat glass

surface for producing a scanned copy.

Hand Held Scanner: This scanner is used by dragging it over the

object that is to be scanned.

Microphone

o It is used to send voice signals to a computer.

o It receives sound waves and converts them into electrical signals to be

used by the computer.

Light Pen

o It is a pointing device used to draw on the monitor.

o It senses the screen by using the sensor on the tip and converts the

information into digital signals.

Digital Camera

o It is used to take photographs.

o Data cable is used to transfer the photographs from the camera to the

computer.

o Memory card is used to store the photographs.

2. Output devices: It is used to display the output. Example – monitor, printer, plotter,

speaker, projector.

Monitor

It shows the output on the screen.

It is also known as visual display unit(VDU).

The image on the screen is formed by the tiny dots known as pixels.

The quality of a monitor depends upon the number of pixels present on the

screen.

Types of monitors:

o CRT (Cathode ray tube) – This monitor has a CRT fixed inside it. Tiny

red, green and blue phosphor dots glow to create an image on the

screen. These monitors are bulky.

o LCD (Liquid crystal display)-This type of monitor has a flat panel.

These monitors are light in weight and consume less energy.

Printer

It helps to take the hard copy of the output on a paper.

The three types of printers are:

• Dot Matrix Printer

o It contains a movable print head with pins that strike the ribbon

placing a dot on the paper with hundreds of dots forming images

or text.

o The speed of this printer is given in CPS (Character per second).

• Inkjet printer

o It forms letters and images on the paper by spraying small

streams of quick drying ink.

o The speed of this printer is given in LPM (line per minute)

• Laser printer

o It uses laser technology to print images on the paper.

o The speed of this printer is given in PPM (pages per minute)

LCD projector

It is used to display videos, images or data on a larger screen.

It projects the images onto the surface by passing light over an LCD

panel.

3. External Storage Devices

Storage devices help store data and information. The storage device of the computer

system is known as computer memory.

It consist of devices like

CD – It stands for compact disk. It can hold up to 700 MB data. It is of three types:

o CD ROM – Compact disk read only memory

o CD R – Compact disk recordable

o CD RW – Compact disk read write

DVD

o It stands for Digital Versatile Disk.

o It is used to store more data as compared to CDs.

BLU ray

o It is a scratch resistant disk used to store large amount of data.

o It uses blue-violet laser light to store data on the disk.

o They are highly reliable for storing data for a long time.

Pen drive

o It is a portable storage device used to transfer data from one computer to

another.

o It is also known as flash drive.

o These are the most commonly used portable devices because of its small size

and faster data transfer rate.

Hard disk

o It is used to store large amount of data.

o It is the main storage device fixed inside the CPU cabinet.

o It can store data ranging from 500GB to 5 TB.

o Data is stored magnetically on the multiple disks made of a rigid material

known as platters.

o Portable hard disks are used to store more data.

o All the application software is stored on the hard disk.

Question Bank

(Chapter 1)

Objective type Questions.

A. Name any two types of each of the following:

1. Printer ___________ ___________

2. Monitor ___________ ___________

3. Port ___________ ___________

4. Keyboard ___________ ___________

5. Input device ___________ ___________

6. Output device ___________ ___________

7. Storage device ___________ ___________

8. RAM ___________ ___________

9. ROM ___________ ___________

10. Scanner ___________ ___________

B. Fill in the blanks.

1. A CPU is considered to be the ______________ of a computer system.

2. A monitor is also known as _______________.

3. The printed copy of the output is known as _____________.

4. ___________ is known as the graphics card.

5. ___________is known as the scratch resistant disk.

C. Write the full form of the following terms:

1. RAM

2. ROM

3. PROM

4. EPROM

5. EEPROM

6. SMPS

7. DVD

8. CD ROM

9. CRT

10. LCD

11. ALU

12. CPU

13. VGA

14. USB

15. PCI

Subjective Type Questions A. Short Answer Type Questions.

1. Which scanner is mostly used in shopping stores?

2. Which device is responsible for supplying electric power to all parts of a

computer?

3. Which port is used to connect mouse/keyboard to IBM compatible

computers?

4. Which component of CPU receives data, holds it and delivers according to

the instructions?

5. Which electronic card provides input and output audio signals to and

from a computer?

B. Long Answer type questions.

1. Differentiate between

a. Hardware and Software

b. RAM and ROM

c. Serial and Parallel Port

d. Input and Output Devices

e. Internal and External hardware

f. Video card and Sound Card

2. Describe the working of a modem.

3. Define PCI and motherboard.

4. What is heat sink? Name its types.

5. What is the use of SMPS?

6. In what ways are DVDs more useful than the CDs?

7. What are the main functions of a CPU? Explain its components.

Question Bank

(Chapter 1)

Answer key

Objective type Questions.

A. Name any two types of each of the following:

1. Printer - Inkjet, laser, Dot-matrix (Any two)

2. Monitor - CRT, LCD, LED (Any two)

3. Port -Serial, Parallel , VGA, USB (Any two)

4. Mouse -Optical, Wireless, Trackball, Mechanical (Any two)

5. Input device -Keyboard, mouse, joystick, Light pen, microphone, digital

camera, scanner (Any two)

6. Output device -Monitor, Printer, projector

7. Storage device – Hard disk, pen drive, flash drive, DVD, CD (Any two)

8. RAM -Static, Dynamic

9. ROM -PROM,EPROM,EEPROM (Any two)

10. Scanner -Flatbed, handheld scanner

B. Fill in the blanks.

1. A CPU is considered to be the brain of a computer system.

2. A monitor is also known as visual display unit.

3. The printed copy of the output is known as hard copy.

4. Video Card is known as the graphics card.

5. Blu-ray is known as the scratch resistant disk.

C. Write the full form of the following terms:

1. RAM - Random Access Memory

2. ROM – Read Only Memory

3. PROM – Programmable Read Only Memory

4. EPROM – Erasable Programmable Read Only Memory

5. EEPROM – Electrically Erasable Programmable Read Only Memory

6. SMPS – Switched Mode Power Supply

7. DVD – Digital Versatile Disk

8. CD ROM- Compact Disk Read Only Memory

9. CRT – Cathode Ray Tube

10. LCD – Liquid Crystal Display

11. ALU – Arithmetic Logic Unit

12. CPU – Central Processing Unit

13. VGA – Video Graphics Array

14. USB – Universal Serial Bus

15. PCI – Peripheral Component Interconnect

Subjective Type Questions A. Short Answer Type Questions.

1. Hand held scanner

2. SMPS

3. PS/2

4. Memory Unit

5. Sound Card

B. Long Answer type questions.

(Please refer to the notes and find the solution. Students should be encouraged

to answer the questions in their own words.)

Practical Activity

Steps to create an electronic spreadsheet

Open MS EXCEL.

Create a timetable for your day to day activities in MS EXCEL.

Apply the formatting as per your imagination/creativity.

For example

Days/Time 10-11 11-12 12-1 1-2 2-3 3-4 4-5 5-6

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday