UNIT -1
INFORMATION TECHNOLOGY
CHAPTER -4
INPUT/OUTPUT DEVICES
1. Why are input and output devices necessary for a computer system?
Input devices are that accepts data from outside world and translate them into a form, a computer can interpret. Main purpose of output devices is to receive information from the computer and supply them to users. The computer sends information to the output devices in binary forms. The output devices convert them into a form that can be understood by users.
2. What are peripheral device? Why they are so called?
Computer peripherals, or peripheral devices, are sometimes called "I/O devices" because they provide input and output for the computer. Some peripherals, such as external hard drives, provide both input and output for the computer.
3. What are graphic input devices? List and explain various types of graphic input devices?
Graphical input devices permit the user to select something on the screen by pointing to it.
a. Mouse
b. Joystick
c. Trackball
d. Track pad
e. Track point
f. Light pen
g. Touch screen etc..
Mouse: Mouse is the popular pointing device. It is a small hand-held device that fits comfortably in user's palm.
Optical Mouse : An optical mouse is an advanced computer pointing device that uses a light -emitting diode(LED). and optical sensor.
Trackball : A trackball is a cursor control device used in many notebook and laptop computers. The trackball is usually located in front of the keyboard towards the user. Now a days it is replaced by touch pad.
Track pad: It is one of the latest pointing devices.
Track point : This device is also called as eraser pointer because it resembles the shape of a pencil
eraser.
Joystick :Joystick is a pointing device used to move the cursor position on a screen.
4. What is an input device? Name some commonly used input devices?
An input device is a piece of hardware used to provide data to a computer used. Commonly used input devices are
Keyboard, Mouse, Optical Mark Reader ,Bar Code Reader ,Track ball etc.
5. Briefly explain laser printer?
Laser printers are non-impact type printers. They print one page at a time. These printers use laser beam to produce an image on a photosensitive drum. The image is transfered from drum to paper using toner. Toner is an electrically charged ink.
6. Briefly describe ink-jet printer.
These are non-impact printers that form characters and images by spraying small droplets of ink on a paper. A special type of iron content ink is used. Droplets of ink are electrically charged by an electrode. Inkjet printers are used for colour printing.
7. Differentiate between mechanical and optical mouse?
A mechanical mouse has a ball that turns rollers inside. If friction is lost between the ball and the mouse surface, or between the ball and the rollers, the mouse fails to work.
An optical mouse is an advanced computer pointing device that uses a light -emitting diode(LED). and optical sensor. An optical mouse uses light to detect movement. They work by emitting light from an LED or laser.
8. What is plotter?
Plotters are pen-based output devices that are used to produce high quality and clarity output. It is mainly used to draw pictures and graphics.
9. What is track ball? How it is different from a mouse?
A trackball is a cursor control device used in many notebook and laptop computers. The trackball is usually located in front of the keyboard towards the user.
Mouse is the most popular pointing devices that fits comfortably under the palm of your hand. With a mouse, users control the movement of the pointer.
10. What is LCD? Differentiate between CRT and LCD monitors?
LCD (Liquid Crystal Display) are super thin displays that are used in laptop computer screens and flat panel monitors. LCD screens are based on the principle of blocking light. Advantages are light weight, compact and clarity output.
CRT LCD
1. Cathode Ray Tube 1. Liquid Crystal Display
2. It consumes more power. 2. It consumes less power.
3. CRT is cheaper than LCD 3. LCD is costlier than CRT
4. Size is large 4. Size is smaller than CRT
5. Low resolution 5. High resolution so picture quality is good.
11. Explain the printing mechanism of dot matrix printer ?
They print characters and all kinds of images as patterns of dots. It has a print head that moves horizontally across the paper The print head contains an array of pins?(called matrix).The printer can activate each pin independent of others to extend and strike against an inked ribbon to form a dot on the paper.
12. What is the use of computer output microfilm?
Computer output microfilm technology is used to record computer output information as microscopic filmed images. In COM ,information are recorded on a sheet or microfilm .Data from computer into language and records it on microfilm.
13. What do you mean by hard copy and soft copy?
A hard copy is a printed document. When a document is created on a computer , it is typically saved as a file on the computer's hard drive. This is a soft copy of document.
14. Differentiate between impact and non impact printers?
Impact printers are printers which works by creating a direct contact between ink ribbon and paper. These printers are noisy yet popular. Impact printers have mechanical moving parts to conduct printing. Examples: Dot-matrix printers, Daisy-wheel printers, and line printers.
Non-Impact printers don't uses any direct contact between ink ribbon and paper. They use laser, xerographic, electrostatic, chemical or inkjet technology. These printers are less noisy and don't have mechanical moving parts to conduct printing. Examples: Inkjet printers and Laser printers.
Objective type questions and answers
1. Mouse and light pen are examples of -------------------input devices.
Ans. Graphical
2. MICR stands for --------------------------- .
Ans. Magnetic Ink Character Reader
3. The most common layout of a keyboard is -------------- .
Ans. QWERTY
4. LCD stands for ------------------
Ans. Liquid Crystal Display
5. -----------------is an input device used for playing computer game.
Ans. Joystick
6. Touch screen is a ----------- device .
Ans. Input
Essay type questions (Ref. text book)
1. What are pointing devices? Discuss some of the commonly used pointing devices?
2. What are scanners? list and explain various types of scanners?
3. What is an output device? List some commonly used output devices.
