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

 

Class: - 7

Subject Computer

Ch 1 COMPUTER - EXTERNAL HARDWARE

 

Ex.5 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.

(f) 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.

(g) 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 scanner.

(h)MICR: -

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 sentences.

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.

Q.2 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 clearly.

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).

Laser Printer: - This 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?

Ans:- 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

Q.l 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 Uses

     l. 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 stand.

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

There 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 times.

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.

Q.5What 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.