COMPUTER – EXTERNAL HARDWARE |Ch 1| Computer Science | ICSE| STD 7th


Class: – 7

Subject Computer



Define the following: –

(a)  Track Ball: –

The track ball is similar to the mouse, but the roller ball
is mounted on the top and the user spins the ball with thumb, fingers or the
palm in various directions to effect cursor movements. It is normally used in a
laptop PC.

(b)  Touch Pad: –

A touch pad is a flat, pressure-sensitive surface that is
used in notebook computers. We can move the mouse pointer by moving our finger
along the surface of the pad.

(c) Motion input: –

Motion input lets the user guide on-screen elements using air gestures.
Air gestures involve moving our body or a handheld input device through the
air. With motion input, a device containing a camera, detects our gesture and
then converts it to a digital signal.

(d)   Graphic Tablet: –

Graphic Tablet, also called Digitizer, is an input device
which has a special pen (stylus) to write on it. It is used to draw images om
the computer as well as to give instructions to the computer.

(e)   Webcam: –

A Web camera (or webcam) is a real-time camera that enables a
user to capture video and still images, make video telephone calls, etc. Web
cameras usually come with software that helps us set up and use the Web camera.

Digicam: –

A digital camera, also called digicam, is an electronic input
device used to capture and store photographs electronically in the computer,
instead of using photographic film used in conventional cameras.

Barcode Reader: –

Most products in the shops have barcode on them. A barcode is
a set of lines of different thickness that give information about the product
like its price, manufacturing data, etc. Barcode reader, also called a barcode

(h)MICR: –

reader is an input device used to read and identify magnetized characters
printed on a document such as cheque.

Ex. 7 Answer in 1-2

Q.l What is a computer system?

Ans: – A
computer is called a computer system, as it is not a single machine but a
collection or combination of many devices which work together
to perform a task.

How will you classify external hardware?

Ans: – The
hardware components that are attached outside the computer case or system unit
are external hardware. Keyboard, monitor, mouse, printer, scanner, etc. are
external hardware.

Q.3 What is the use of Data Projector?

Ans: -A
data Projector is an output device that projects the data, being displayed on a
computer screen, on a larger screen so that and audience can see the image

Q.4 Differentiate between Impact and
Non-Impact Printer

Ans: –
Impact printer:-
Printers that have direct contact between printer head and
paper are known as impact printer.

Non-Impact Printer:- Printers that do not have direct
contact between printer head and paper are known as non-impact printer.

Q.5 Write a short note on Dot Matrix Printer
and Laser Printer.

Ans:- Dot Matrix Printer:- This printer is an impact
printer that contains movable print head with pins that strike the ribbon,
placing a dot on the paper. These printers are less expensive, but are very
noisy. The speed of this printer is given in cps (Characters per second).

Printer: –
printer is a non-impact printer that uses laser technology to print text or
images on paper. It gives the best quality output and is expensive. The speed
of this printer is given in ppm (pages per minute).

Q.6 What are the features of a flash drive?

Flash drives, also known as Pen drives, are one of the newest forms of computer
storage devices that plug in a USB port on a computer. Pen drive is portable
and lightweight. It has a storage capacity ranging from 512MB to 100 GB, and
transfer data at a very high speed.

Ex. 8 Answer Briefly

What do you mean by Hardware? What are its components?

Ans: – All
the physical and mechanical devices attached together to make a computer system
are called hardware. We can see or touch the hardware. There are two kinds of
hardware components: – External and Internal.

External hardware: – The hardware components that are
attached outside the computer case or system unit are external hardware. Ex.
Keyboard, Monitor, Mouse.

Internal hardware: – The hardware components that are
fitted inside the system unit are internal hardware. Ex. CPU, motherboard,
drives, power supply etc.

Q.2 Define Touch screen. Write any three
gestures and common user of touch screen.

Ans: – A
touch screen is a screen that we can touch with our finger to input
information. Our finger acts as the pointing device. Tablet PC, Smartphone, and
ATM use touch screen to input instruction.

Any three gestures: –

        Motion                                          Common

Tap                                 Activates
a link or presses a button.

2.      Swipe                            Scrolls

3.      Pinch                              Zooms out

Q.3  What is the use of output
device? Explain Smart board and Plotter.

Ans: – An output device is any hardware
component that can convey information to a user. Some commonly used output
devices are display devices Monitor, Printers, and speakers.

Smart board: – A smartboard is an output device that
displays the image on a connected computer screen, usually via a data projector.
Notes written on the smartboard can be saved directly on the computer. These
are used frequently in classrooms as a teaching tool and to enhance the
delivery of presentations. The smartboard can be hung on a wall or mounted on a

Plotter: – Plotter is a sophisticated printer
used to produce high-quality drawings such as blueprints, maps, and circuit
diagrams, This printer is used in specialized fields, such as engineering and
drafting, and are usually very costly. The plotters are of the following four
types: Drum Plotter, Flatbed Plotter, Electrostatic Plotter and Inkjet Plotter.

Q.4  Define optical disc and
explain its types.

Ans: – An optical disc is a type of storage
media that consists of a flat, round, portable disc made of metal and plastic.
Some optical disc formats are read only. Some optical disc are read and write
which allow users to save data on the disc just as they save on a hard disk

are some types of optical disc.

1, Compact Disc: – A Compact Disc is a  metal storage medium that is usually 4.75
inches in diameter, and less than one-twentieth of an inch thick. Two basic
types of compact disc designed for use with computers are CD-ROM and DVD-ROM.

2.      Recordable CD (CD-R) and DVD (DVD-R):
– A CD-R and DVD-R are multi-session compact discs on which we can record our
own items such as text, graphics, and audio.

3.      Re-writable CD (CD-RW) and DVD
(DVD-RW):- A CD-RW and DVD-RW are erasable disc that allow us to write multiple
times. These discs act like a hard disk, allowing us to write and rewrite data and information on it multiple

4.      Blu-ray Disc: – Blu-ray is a new DVD
format, which has a higher capacity and better quality than standard DVDs. A
Blu-ray Disc-ROM has storage capacity of 100GB.Blu-ray Disc drives and players
are used to play or run Blu-ray discs.

are communication devices? Explain the purpose of Modem.

Ans: – A
communication device is any type of hardware capable of transmitting data,
instructions and information between a sending device and a receiving device.
Computers process data as digital signals.

Modem: – A
modem is a communication device. The word modem, is derived from a combination
of the words, modulate, to convert digital signals to analog signals and
demodulate, to convert an analog signals to digital signals, so that data can
travel along an analog telephone line.

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