bishop cotton school, shimla computer science class 7 ......primary memory is divided into two...
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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
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