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Chapter 1 - Unit 2

External Hardware

Class 7 - APC Understanding Computer Studies


Choose the correct option

Question 1

Which of the following is called the physical part of a computer system?

  1. Hardware
  2. Utility programs
  3. Application software
  4. System software

Answer

Hardware

Reason — Hardware refers to the physical devices of the computer.

Question 2

What type of device a computer mouse is?

  1. Communication device
  2. Output device
  3. Pointing device
  4. System device

Answer

Pointing device

Reason — A mouse is popularly known as a pointing device.

Question 3

Which of the following devices is used to track the movement of people for security purposes?

  1. Digital camera
  2. Webcam
  3. CCTV camera
  4. Phone camera

Answer

CCTV camera

Reason — CCTV (Closed-Circuit television) is a TV system that is used for surveillance and security purposes.

Question 4

Which of the following is the most appropriate statement of dot matrix printer?

  1. It is very costly.
  2. Printing quality is very high.
  3. It prints the characters or images by a striking mechanism.
  4. It is a non-impact printer.

Answer

It prints the characters or images by a striking mechanism.

Reason — Dot Matrix printer is an impact printer that forms characters or images by a striking mechanism.

Question 5

What another name is given to a pen drive?

  1. Flash drive
  2. Small drive
  3. Hard drive
  4. Soft drive

Answer

Flash drive

Reason — Pen drives are also called Flash drives as they use flash memory store files.

State whether the following statements are True/False

Question 1

Input devices are used to feed the data and instructions in the computer system.
True

Question 2

A mouse is popularly known as a pointing device.
True

Question 3

You cannot receive or send a fax through an all-in-one printer.
False

Question 4

A cordless mouse or a keyboard works within a short range of distance from your computer system.
True

Question 5

A scanner can be compared to a photocopy machine.
True

Question 6

A light pen is used in computer aided designing (CAD).
True

Question 7

A scanned image cannot be sent to an e-mail editor.
False

Question 8

Digital photographs have low resolutions as compared to other photographs.
False

Question 9

A touchscreen is a menu-driven input device.
True

Question 10

A liquid crystal display (LCD) screen consumes less power and also radiates less heat.
True

Write the full forms of the following

Question 1

LCD

Answer

Liquid Crystal Display

Question 2

SD Card

Answer

Secure Digital Card

Question 3

CPS

Answer

Character Per Second

Question 4

CAD

Answer

Computer Aided Designing

Question 5

RPM

Answer

Revolution Per Minute

Question 6

CRT

Answer

Cathode Ray Tube

Name the following

Question 1

Four input devices

Answer

  1. Mouse
  2. Keyboard
  3. Joystick
  4. Scanner

Question 2

Four output devices

Answer

  1. Speaker
  2. Monitor
  3. Printer
  4. LCD Projector

Question 3

Two types of impact printers

Answer

  1. Dot Matrix Printers
  2. Daisy Wheel Printers

Question 4

Two types of non-impact printers

Answer

  1. Inkjet Printers
  2. Laser Printers

Question 5

Two pointing devices

Answer

  1. Mouse
  2. Light Pen

Question 6

Two secondary storage devices

Answer

  1. Hard disk
  2. DVD

Case-Study Based Questions

Question 1

There are some devices in a computer system which are used to give out the result of data processing. A popular output device about which you would be well aware of resembles a TV screen. In case, the output is to be displayed on a big screen for showing it to numerous people, an LCD projector is used. Other than these devices, we can also use printers (impact and non-impact) to produce the output on paper.

Based on the above case, answer the following questions:

(a) Which of the following devices resemble a TV screen?

  1. Touch sensor
  2. VDU
  3. MCB
  4. All of the above

(b) Which device produces result on paper with hammering effect?

  1. LCD projector
  2. Laser printer
  3. Dot Matrix printer
  4. Inkjet printer

(c) Which of the following devices produce result without making any sound?

  1. Impact printer
  2. Character printer
  3. Dot Matrix printer
  4. Laser printer

(d) Which of the following devices is used to display presentation in a hall or a gallery?

  1. Digital camera
  2. Laptop screen
  3. LCD projector
  4. Seven segment display

Answer

(a) VDU

(b) Dot Matrix printer

(c) Laser printer

(d) LCD projector

Define the following terms

Question 1

SD card

Answer

Secure Digital card is an ultra small flash memory or a non-volatile memory card designed to provide high capacity memory in a small size. It measures 32 X 24 X 2.1 mm and weighs approximately 2 grams.

SD cards are used in many small portable devices and the storage capacity varies from 1 GB to 16 GB.

Question 2

Mouse

Answer

A mouse is a pointing device. It is connected to the CPU. It consists of a roller at the bottom on which the upper part rolls. An optical mouse may not contain a roller but has a light source at the base to detect the position of the cursor.

A mouse has two or three buttons and a scroller. It moves on a soft rubber pad. With the movement of the mouse, a pointed arrow moves on the screen. The arrow on the screen is used to select items from the menu. The mouse cursor is taken to the desired place and then clicked to get the task done.

Question 3

Scanner

Answer

It is an input device which allows the user to take the images of the text and photographs from the source. The images can be saved on to the disks for further processing.

The document is placed on the glass scanning surface and a mechanically-driven scan head passes beneath it. The scanner captures high resolution images with outstanding quality that can automatically be sent for further processing.

Question 4

Visual Display Unit

Answer

A Visual Display Unit is an output device. It is similar to television screen having a cathode ray tube. A CRT consists of three main parts — electron gun, deflecting plates and a fluorescent screen.

A CRT converts electrical signals into visual signals. A computer screen receives digital signals and the resolution in a computer screen can be changed as per requirement. The size of the monitors varies from 8 inches to 21 inches.

Question 5

LCD Projector

Answer

A Liquid Crystal display projector is an output device used to magnify the presentations prepared on a computer. It accepts data/information from the CPU.

With the help of a small LCD panel, the data is fed and then passes through a convex lens. The presentations are then received on the screen in a magnified form.

These projectors are widely used in seminars, for demonstrations, in classrooms and in cinemas.

Question 6

Inkjet Printer

Answer

Inkjet Printer is the most commonly used non-impact printer. It has a fine nozzle through which a very fine stream of ink is ejected. The flow of ink is controlled in such a way that the impression of the character appears on the paper. These printers make very little noise and produce high quality graphics. The speed of an inkjet printer varies between 50-300 characters per second.

Question 7

Light Pen

Answer

It is a pointing device which has a pen-like structure. Inside the pen, there is a photo sensor which detects light. The pen is placed on the screen of the monitor that sends light signal. The photo sensor transmits its equivalent signal to the CPU. This enables us to draw a picture directly on the screen. The pen is generally used in computer aided designing (CAD).

Differentiate between the following

Question 1

Impact printers and Non-impact printers

Answer

Impact PrintersNon-Impact Printers
It forms characters by striking a print hammer against an inked ribbon.It forms characters without making direct contact with the paper.
It uses either ribbon or carbon paper.It uses ink cartridges.
It makes noise while printing.It prints smoothly on the paper.

Question 2

Input devices and Output devices

Answer

Input DevicesOutput Devices
Input devices are used to accept data and instructions by the computer.Output devices are used to get the results of any processed data.
For example — Mouse, Keyboard.For example — Speaker, Printer.

Question 3

Keyboard and Mouse

Answer

KeyboardMouse
It is similar to a typewriter that enables the user to enter data into the computer.It is a pointing device which is used to move the cursor all over the screen.
It has more than 104 keys on it.It has two or more buttons on it.
It is used for typing.It is used for selecting objects, playing games, making drawings etc.

Long Answer Questions

Question 1

What is a printer? What are its types?

Answer

Printers are common output devices used to get the results on paper. They provide information in a permanent and readable form. The data/information is transferred from the main memory of the computer to the printer and then printed on the paper.

Printers are of two types:

  1. Impact printers
  2. Non-impact printers

Question 2

Explain the three functions of a scanner.

Answer

The three functions of a scanner are-

  1. Scan — It captures the images that can be saved as a file or sent to an image editing application.

  2. Copy — It scans the images and sends it to the printer to get a hard copy at the same time.

  3. E-Mail — It scans the images and delivers it directly to the e-mail editor.

Question 3

How is a web camera useful to us?

Answer

Web cameras are the most common video capturing devices connected to computers. They can be used for video chatting over the internet. Webcams allow real-time communication from anywhere in the world. They can also be used for security purposes and to reach millions of mainstream PC users worldwide.

Question 4

Explain the working principle of a Laser printer.

Answer

In a Laser printer, a low power laser beam is used to create an image of the page to be printed on the photo-conducting surface of a rotating drum. A special ink (toner) is used which is attracted to the laser-exposed surface of the drum. When the paper comes in contact with the drum, the image is fixed on to the paper.

Question 5

What is meant by a flash drive? Why is it so popular?

Answer

A flash drive is a portable data storage device. It is re-writable and holds the data in memory without power supply. It fits into any USB port of a computer. The drive is small, of the size of a human thumb and is a very stable memory storage device.

We can save text, music, documents and photos in this drive. The storage capacity of a flash drive is 32 GB or more. It is an ideal data storage device because at a low price, it offers long-term storage.

Question 6

What are the points to be considered while selecting a printer?

Answer

The selection of a printer depends on the following features:

  1. Quality of printing — It means whether the impression of characters on paper is in the form of dots or letter quality.
  2. Speed of printing — It refers to the speed with which the printing of characters takes place on the paper. This specification is decided by CPS (Character Per Second) or RPM (Revolution Per Minute) marked on a printer.
  3. Type of printer — It means whether it is an impact printer or a non-impact printer.
  4. Cost of printer — Of course, the cost matters while selecting a printer. But, we always look for the cheap and best quality to fulfil our requirements.
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