SOLUTION FOR CLASS 9 CHAPTER PERIPHERAL DEVICES

A. Fill in the Blanks:

1. A speaker converts an alternating electrical current into Sound.

2. Laser printers use a laser beam and Powdered ink to produce the fine print.

3. A Plotter is a vector graphic printing device

4. Hard disk is made up of a collection of disks known as Platters.

5. Flash drive is plugged into the computer USB port.

B. State True or False:

1. A joystick is a small instrument shaped like a pen used to provide input to mobiles, monitors, and tablets.

Ans. False

2. A bar code is a computer-readable representation of information, present in a visual format.

Ans. True

3. A monitor is also called a Visual Display Unit (VDU).

Ans. True

4. The picture on a monitor is made up of thousands of small colored dots called Pixars.

Ans. False

5. LED monitors offer better color quality, clarity, and display than the LCD monitors.

Ans. True

C. Answer the Following Questions:

1. What are peripheral devices? Give some examples.

Ans. A computer system is made up of three major units that carry out its primary functions- Input, Output, and storage units. There are many other internal and external devices that connect to the computer directly and add functionality to it. These devices are called peripheral devices.

Example- CD ROM Drive, Printer, Monitor, Modem, Digital camera, etc.

2. What is a Scanner? What are its types?

Ans. The scanner is an input device that scans text images and objects optically. The scanned data is then converted into a digital image and displayed on the computer screen. 

There are three types of scanners:- 1. Drum Scanner 2. Flatbed Scanner 3. Handheld Scanner.

3. What do you understand by a Monitor? Define pixels.

Ans. The monitor is the most common output device. It is also called the Visual Display Unit (VDU), an electronic visual display for computers. Just like a television, a monitor also displays the output on the screen.

Monitor display pictures by dividing the display screen into thousands(or millions) of minute dots called pixels, arranged in rows and columns. The pixels are so close together that they appear connected.

4. What is HDD? Briefly explain its configuration.

Ans. A hard disk is the most common storage device for storing a large amount of data. It is also called HD or HDD( Hard Disk Drive) or Winchester disk. It was introduced in 1954 by an IBM team lead by Ray Johnson. The disc rotates at a very high speed varying from 5400 to 15,000 RPM (Rotations Per Minute).

Hard disk is made up of a collection of disks known as platters. Each platter requires two read/write heads one for each side. All the read/write heads are attached to a single Access arm so that they do not move independently. Each platter has the same number of tracks to store data. A track location that cuts across all platters is called a Cylinder.