Input/ Output Devices

Ch :3. lnput/ Output Devices

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Q.1. Define input and input devices. Name the categories of input devices.

Ans : Input

Anything given to the computer is known as input. The input can be given in different forms such as text, image and sound etc.

Input Devices

The devices that are used to give data and instructions to the computer are known” as input devices. The input devices convert data and instructions into a form that can be processed by computer. These devices send this data to the processing unit for processing.

Categories of Input Devices

Different categories of input devices are as follows:

  • Keyboard
  • Pointing devices
  • Scanning devices
  • Voice input devices
  • Digital camera

Q.2. What is a keyboard? Explain different categories of keys on keyboard.

Ans : Keyboard

Keyboard is the most commonly used input device. It is used to enter data into the computer. The layout of keyboard is similar to a traditional typewriter. It also contains some extra command keys and function keys. The buttons on the keyboard are called keys. The most popular keyboard layouts are QWERTY and DV orak. The layout refers to the arrangement of keys on the keyboard. A typical keyboard contains 101 to 104 keys.

Categories of Keys on Keyboard

Different categories of keys on keyboard are as follows:

  • Alphanumeric keys
  • Numeric keys
  • Function keys
  • Cursor control keys

1. Alphanumeric Keys

Alphanumeric keys are used to enter alphabets, numbers and other special characters.

The position of these keys on keyboard is similar to typewriter.

Different alphanumeric keys are as follows:

Alphabet Keys These keys are from A to Z including uppercase and lowercase letters. The arrangement of these keys is known as QWERTY A layout. This is because the first six keys on the top row of the keyboard are Q, W, E, R, T, Y.

Number Keys These keys are from 0 to 9.

Special Characters Keys These keys consist of punctuation keys, special characters and space bar etc.

2. Numeric Keys

Numeric keys are located on the right side of most keyboards. These keys are used to enter numeric data from 0 to 9. These keys are also used to enter mathematical symbols such as plus +, minus -, multiplication * and division / . NumLock key is used to lock and unlock the function of numeric keys.

3. Function Keys

Function keys are used for performing different function depending on the application being used. These keys provide the shortcuts to perform routine tasks on computer. Most keyboards have a row of function keys on the top of keyboard. These keys are marked from F1 to F12. Many programs support the use of function keys. The function keys are frequently used in combination with special keys such as CT RL, ALT and SHIFT keys.

4. Cursor Control Keys

The cursor represents the position where keyboard’s input will be placed. The cursor control keys are used to control the position of cursor. These keys are also known as arrow keys. These keys move the cursor from its current position to right, left, up or down. These keys are also used for screen navigation.

5. Additional Keys

Some additional important keys on the keyboard are as follows:

Enter Key It is used to enter commands or to move the cursor to the beginning of next line. It is also labeled as Return instead of Enter.

ESC Key It is used to terminate a command or current task.

Delete Key It is used to delete the character to the right side of the cursor. It is also used to delete the selected object.

Backspace Key It is used to delete the character to the left side of the cursor. It also moves the position of the cursor to left side.

Caps Lock Key It is a toggle key. It is used to display the letters in uppercase when it is turned on.

Home Key It is used to move the cursor to the beginning of the line or page. Its effect depends on the position of the cursor and the program being a used.

End Key It is used to move the cursor to the end of the line or end of page. Its effect depends on the position of the cursor and the program being used.

Ctrl Key It stands for control. It is used in with other keys to perform specific tasks. The meaning of each control character depends on the program being used.

Alt key It stands for alternate. It is used in with other keys to perform specific tasks.

Tab Key It is used to move the cursor to next tab stop.

Page Up Key It is used to move the cursor one page up at a time. It is abbreviated as PgUp on the keyboard.

Page Down Key It is used to move the cursor one page down at a time. It is abbreviated as PgDn on the keyboard.

Insert Key It is used to switch between Insert Mode and Overtype Mode. It is a toggle key. .

Spacebar Key It is used to insert single space. It also moves the cursor to right side.

Q.3. Write a note on mouse. Describe different mouse events.

Ans : Mouse

Mouse is a pointing input device. It is used to input instructions with a pointer on the screen. Mouse is moved on a flat surface to control the movement of the cursor or pointer on the screen. A mouse usually has two or three buttons. These buttons are used to perform different tasks such as selecting an object or opening a program etc. It may also include a wheel to scroll through long documents.

There are different types of mice. Two main types of mice are mechanical and optical. A mechanical mouse uses a ball to control the pointer on the screen. An optical mouse uses laser light to control the pointer. Optical mouse is becoming popular now a days. It is expensive than mechanical mouse.

Mouse Events

An activity that can be performed by using the mouse is known as mouse event. A typical mouse can perform the following events:

1. Left Click It is the most frequently used mouse event. This event occurs when left mouse button is pressed. .It is. used to select a graphical object such as an icon or text in a document. It is also used to press a button, close, open or minimize window etc.

2. Right Click This. event occurs when right mouse button is pressed. It is used to view the properties of an object such as file, folder or desktop etc.

3. Drag This event occurs when the mouse is moved while pressing left mouse button. It is used to select multiple items at a time. It is also used to move an object from one location to another.

Q.4. What is trackball?

Ans : Trackball

A trackball is a pointing input device. It works like a mouse. It contains one to three buttons. It has a large rotating ball on the top. The body of the trackball is not moved. The ball is rolled with the fingers or palm of hand. The position of the cursor on the screen is controlled by rotating the ball.

The advantage of trackball is that it remains stationary. It does not require much space for use. It can be placed on any type of surface. Trackball is very popular input device for portable computers. It can also be used as separate input device with desktop computers.

Q.5. What is the use of joystick?

Ans :  Joystick

Joystick is an input device used for games, computer aided designs or simulations. It is like a leveler that moves in all directions. It is used to control the movement of pointer or some other object.

A joystick can perform a similar function to a mouse. There is a difference between mouse and joystick. The Pointer on screen st0P5 moving When the movement of mouse is stops. However, the pointer continues to move in the direction to which the joystick is pointing. The joystick has to move to its neutral position to stop the pointer.

Q.6. What is scanner?

Ans : Scanner

A scanner is an input device. It is used to read the pictures and other printed material placed on its glass. It scans a whole page at once. It reads the picture, translates it in digital form and stores it in computer. The information is stored in the form of image or picture and not in the form of text. Optical Character Recognition (OCR) software is required to read the image and convert it to actual text.

Scanners are available in the following different types:

  • Monochrome scanners
  • Flatbed scanners
  • Color scanners

Q.7. Write a note on microphone.

Ans : Microphone

A microphone is an input device. It is used to digitally record audio data like such as human voice. It can be plugged into a computer or recorder. Many software applications can accept data with microphone. It enables a user to input text and issue commands orally. The software in the computer converts the sound waves into digital form. It is then stored in memory and used according to the requirement.

Q.8. What is voice recognition system? Explain.

Ans : Voice Recognition System

A voice recognition system coverts the speech of a person into digital data. It uses microphone as input device. It is done by comparing the electrical patterns of speaker’s voice with a set of prerecorded patterns stored in computer. The voice recognition system allows the user to use voice as input. It enables a user to input text and issue commands orally such as opening programs and using menus etc.

The older voice recognition systems require to separate each word by a distinct pause. It allows the machine to determine the start and end of one word. This style of dictation is known as discrete speech. However, the new systems allow the user to speak continuously.

Q.9. What is light pen?

Ans :  Light Pen

Light pen is a light-sensitive input device. Its shape is similar to a traditional pen. It is used to draw on computer screen or select menus. It is connected by a wire to the computer. It has a device at the tip that emits light. The pen sends information to the computer when user touches the pen on certain areas of a specially designed screen. The information contains the x-y coordinates of the position of pen.

Light pen provides all features of mouse. The user can interact more with application by using Option such as drag and drop etc. It provides more active and accurate interaction between the user and computer system. Light pen is usually used by engineers and graphic designers etc

Q.10. Write a note on digital camera.

Ans : Digital Camera

Digital camera is an input device. It stores images digitally in its memory rather than recording on film. The pictures taken with a digital camera can be downloaded on computer system. The pictures can be processed further with graphics programs. The digital photos are limited by the amount of memory in the camera. The main ‘advantage of digital cameras is that making photos is inexpensive and fast. It does not require any film processing.

Q.11. What is disk drive?

Ans : Disk Drive

A disk drive is used to read and write data on a disk. It has one or more read/ write heads to read and write data. The read/write heads read data from disk and transfer it to main memory for further processing. There are different types of disk drives for different types of disks. A hard disk drive (HDD) reads and writes hard disk. A floppy disk drive (FDD) accesses floppy disks and optical disk drive reads optical disk.

Different types of disk drives are as follows:

1. Internal Disk Drive It is housed within the computer.

2. External Disk Drive It is housed in a separate box that connects to the computers.

Q.12. Define output and types of output. Name important output devices.

Ans : Output

The data that has been processed into useful information is called output. Different types of output are as follows:

1. Soft Copy The output shown on display screen is called softcopy output. The common devices to produce soft copy are monitors and speakers.

2. Hard Copy The output printed on paper is called hardcopy output. The common devices to produce hardcopy output are printers and plotters.

Output Devices

The hardware components that are used to receive information from the computer are called output devices. Output devices take information from the computer and convert it in a form that is understandable by the users.

Some important output devices are as follows:

  • Monitors
  • Printers
  • Plotters
  • Speakers

Q.13. What is monitor? Discuss different types of monitors.

Ans : Monitor

The monitor is the most commonly used output device. It is also known as display or screen. The user looks at monitor while performing different tasks such as typing, issuing commands or surfing the Internet etc. The quality of the image displayed on screen depends on many factors. An important factor that affects the quality of monitor is called resolution. Resolution is the number of pixels on the screen. It is expressed as a matrix. All monitors can be categorized by the way they display colors.

Different categories are as follows:

1. Monochrome Monitor This monitor can display only one color such as green, amber or white. It usually uses black color as background. It can display only text. It is not used to display graphics.

2. Color Monitor This monitor displays the combinations of red, green and blue colors. These are basic colors. A combination of these colors can display full range of colors.

Types of Monitors

Different types of monitors are as follows:

1. CRT Monitor

CRT stands for cathode ray tube. CRT monitor is the most common form of monitor. It consists of a phosphorus coated screen. There are three electron guns on the back of screen. The phosphor coating of the screen is organized into a grid of dots. The smallest number of phosphor dot that can be focused by the gun is called pixel or picture element.

The three electron guns emit beams of three different colors of red, green and blue. Each pixel in color monitor include three phosphors of red, green and blue color. These are arranged in triangle. The phosphors lights up when the beams of three guns are combined and focused on pixel. Different colors are generated with the combination of three colors.

CRT monitor contains a shadow mask mesh made of metal. It is fitted to the shape and size of the screen. The holes in mesh are used to align electron beams. It ensures that electron beams strike correct phosphor dot. The holes are arranged in triangle in most shadow masks.

2. Flat Panel Monitor

Flat panel monitor is small in size. It takes less space and is light weight. It is usually used in portable computers and laptops. It uses less energy than CRT. It is more expensive than CRT monitor. There are different types of flat panel monitors. The most common flat panel monitor is known as liquid crystal display (LCD) monitor.

LCI) monitor creates images with a special kind of liquid crystal. The liquid crystal normally remains transparent but becomes solid when it is charged with electricity. The handheld calculator or digital watch usually uses a liquid crystal display.

Q.14. What is a video controller?

Ans : Video Controller

Video controller is a device between CPU and monitor. The image quality displayed by a monitor is defined by the monitor as well as video controller. It contains memory and circuitry to send information to the monitor for display on screen. The resolution of the monitor is actually determined by the video controller.

Different types of video controllers are as follows:

1. Video Graphic Array (VGA) It has the resolution 640 x 480 pixels.

2. Super Video Graphic Array (SVGA) It has the resolution 1024 x 768 pixels.

Q.15. What is printer? What are different categories of printers?

Ans : Printer

A printer is an output device that prints characters, symbols and graphics on paper. The printed output is called hard copy. Printers are commonly used in businesses to print different documents.

Categories of Printers

Different categories of printers on the basis of printing mechanism are as follows:

1. Impact Printers

An impact printer works like a typewriter. lt prints characters or images by striking a print hammer or set of pins against an inked ribbon. The ink is pressed from ribbon on the paper to produce the output.

Impact printers are the oldest print technologies which are still produced. The impact printers are used where low-cost printing is required.

Three most common forms of impact printers are as follows:

  • Dot Matrix Printers
  • Daisy Wheel Printer
  • Line Printer

2. N on-Impact Printers

A non-impact printer prints characters and graphics on paper without striking paper. The characters are printed on paper with some means such as laser. Some printers use spray ink while others use heat and pressure to create images. These printers are faster than impact printer. However, they are more costly than impact printers. They produce no noise during printing. The print quality of non-impact printers is better than impact printers

Different kinds of non-impact printers are as follows:

  • Laser Printer
  • Electro-thermal Printer
  • Electrostatic Printer
  • Inkjet Printer

Q.16. What is daisy wheel printer? Explain its working.

Ans : Daisy Wheel Printer

Daisy wheel printer is similar to a typewriter. It uses a print wheel. The print wheel is called daisy wheel. Each petal of daisy wheel contains character. A ‘motor rotates the wheel. A hammer strikes a petal against the ribbon when the desired character reaches the position on the paper. This prints the character on the paper. Daisy Wheel printer is slower than dot matrix printer but better in quality.

Daisy wheel printer cannot print graphics. It cannot change the fonts unless the print wheel is physically replaced. These printers are not used in modern computing.

Q.17. What is line printer? Explain its working.

Ans : Line Printer

Line printer is a fast impact printer. lt can print multiple characters on the sam line at a time. Its speed is measured in lines per minute (lpm). The speed range of line printer is from 300 LPM to to 2400 LPM.

The line printers are faster than dot matrix and daisy wheel printers. They are more noisy and provide limited font capability. They produce lower print quality than recent printing technologies. They use special paper that has holes on both sides. This arrangement helps to continue priming at high speed till the paper runs out. Band printer and chain printer are the examples of line printers.

Q.18. What is laser printer? Explain its working.

Ans : Laser Printer

LASER stands for Light Amplification by Stimulated Emission of Radiation. The laser printer is a non-impact printer. Its working is similar to photocopying machine. It uses laser beams to burn special powder on page to create a permanent image. The powder is contained in toner. Laser printer creates high quality output at higher speed. It does not make much noise.

Laser printer prints complete page at a time. It is also known as page printer. It produces very high quality print. It is faster than inkjet and dot matrix printers. Laser printer is mostly used in business field. The printing speed of laser printers is 12 to 150 pages per minute (ppm) or more. The speed depend-s on the contents being printed. The plain text is printed faster than graphics.

Q.19. Write short notes on electro-thermal printer and electrostatic printer.

Ans : Electro-thermal Printer

An electro-thermal printer is a type of non-impact printer. It uses heated pins to burn image on heat-sensitive paper. This type of printers are used in calculators and fax machines. These printers are inexpensive and faster. They produce low quality output.

Electrostatic Printer

An electrostatic printer is a type of non-impact printer. It uses a special photographic paper for printing. It creates characters on the paper by using stylus. The stylus is made of tiny wires. It places an electrostatic charged image on the paper to create characters. The paper is moved through a solution that contains ink particles. The ink adheres to the charges that create a pattern on the paper to develop the image. This type of printer can be used for printing and plotting. It can print more than 5000 lines per minute.

Q.20. What is inkjet printer? Explain its working.

Ans : Inkjet Printer

An ink-jet printer is a type of non-impact printer. It prints characters and graphics by spraying tiny drops of liquid ink on paper. These printers can produce quality text and graphics in both black-and-white and color including photos. A typical inkjet printer provides resolution of 300 dots per inch or more. The latest inkjet printers provide higher resolution.

The price of inkjet printers is less than laser printers. However, they are slower than laser printers. The print quality of inkjet printers is higher than dot matrix printer. They are also comparatively inexpensive Inkjet printers require special type of ink for printing. Most inkjet printers usually have two print cartridges. One cartridge contains black ink and the other contains color.

Q.21. What is a plotter? Discuss different types of plotters.

Ans : Plotter

A plotter is a large scale printer. It receives commands from the computer to make drawings on paper. It creates an output with one ‘or more automatic pens. A plotter can draw continuous point-to-point lines from computer graphics files or commands. Plotters are much expensive than printers. They are frequently used for computer aided engineering (CAE) applications like computer-aided design (CAD) and computer aided manufacturing (CAM).

Q.22. Write a note on CD-R and CD-RW.

Ans : CD-R

CD-R stands for CD recordable. The user can write data on CD-R only once but can read it many times. The data written to CD-R cannot be erased. CD-Recorder or CD Writer is a drive that is used to record information on CD-R disk. The user can record different type of data such as digital audio and video. CD-R can store 700MB of data. It is equal to 80 minutes of digital audio or video. CD-R discs can be used on almost any CD-ROM drive, CD Audio player and CD Video player.

CD-RW 

CD-RW stands for compact disc rewritable. It is also known as erasable optical disk. The user can/read and write data on CD-RW. CD Writer is used to store data on CD-RW disc. The user can write data on CD-RW many times by erasing the existing data. Normally, the user can rewrite 1000 times on CD-RW.

Q.1. Define input.

Ans : Anything given to the computer is known as input. The input can be given in different forms such as text, image and sound etc.

Q.2. Define input devices.

Ans : The devices that are used to give data and instructions to the computer are known as input devices. The input devices convert data and instructions into a form that can be processed by computer. These devices send this data to the processing unit for processing.

Q.3. Write names of some commonly used input devices.

Ans : Some commonly used input devices are keyboard, mouse, scanner and digital camera.

Q.4. What is the use of keyboard?

Ans : Keyboard is the most commonly used input device. It is used to enter data into the computer. The layout of keyboard is similar to a traditional typewriter. It also contains some extra command keys and function keys. The buttons on the keyboard are called keys.

Q.5. Define QWERTY.

Ans : A standard keyboard is normally called QWERTY keyboard. this is because the first six keys on top row of letters on this keyboard are Q, W, E, R, T and Y. .

Q.6. What is the use of function keys?

Ans : Function keys are used for performing different functions depending on the application being used. These keys provide the shortcuts to perform routine tasks on computer. These keys are marked from F1 to F12. Many programs support the use of function keys.

Q.7. Describe cursor control keys.

Ans : The cursor control keys are used to control the position of cursor. These keys are also known as arrow keys. These keys move the cursor from its current position to right, left, up or down. These keys are also used for screen navigation.

Q.8. List some examples of pointing devices.

Ans : Some important pointing devices are mouse, trackball, pointing stick, touch pad, touch screen, light pen, graphic tablet, joystick and pen-based system.

Q.9. What do you know about mouse?

Ans: A mouse is a small and lightweight input device. It is also called pointing device. It is moved on a flat surface to control the movement of the pointer on a screen. The pointer is an object that appears on the screen. It usually appears as an arrow. lt is used to select text and access menus.

Q.10. How does mouse work?

Ans : Mouse is mostly used in graphical applications. lt is moved on a flat surface to control the movement of the pointer on a screen. The mouse buttons are used to perform different tasks. Mouse contains a small ball at the bottom. The movement of the cursor depends on the movement of ball.

Q.11. Define mouse event and name different types of mouse events.

Ans : An activity that can be performed by using the mouse is known as mouse event. A typical mouse can perform different events. These events are left cick, right click and drag etc.

Q.12. State the purpose of trackball.

Ans : A trackball is a pointing input device. It works like a mouse. It contains one to _three buttons. lt

has a large rotating ball on the top. The body of the trackball is not moved. The ball is rolled with fingers or palm of hand. The position of the cursor on screen is controlled by rotating the ball.

Q.13. List any advantage of using trackball instead of mouse.

Ans : The advantage of trackball is that it remains stationary. It does not require much space for use. It can be placed on any type of surface. Trackball is very popular input device for portable computers. It can also be used as separate input device with desktop computers.

Q.14. What is joystick?

Ans : Joystick is an input device us for games, computer aided designs or simulations. lt is like a leveler that moves in all directions. lt is used to control the movement of pointer or some other object.

Q.15. Differentiate between mouse and joystick.

Ans : There is a difference between mouse and joystick. The pointer on screen stops moving when the movement of mouse is stoped. However, the pointer continues to move in the direction to which the joystick is pointing. The joystick has to move to its neutral position to stop the pointer.

Q.16. Describe the use of scanner.

Ans : A scanner is an input device. It is used to read the pictures and other printed material placed on its glass. lt scans a whole page at once. It reads the picture, translates i. in digital form and stores it in computer. The information is stored in the form of image or picture and not in the form of text.

Q.17. How the scanned text is converted into actual text?

Ans : Optical Character Recognition software is required to read the image and convert it to actual text. This software varies widely in its ability to convert text to actual form.

Q.18. What is the use of microphone?

Ans : A microphone is an input device. lt is used to digitally record audio data like such as human voice. lt can be plugged into a computer or recorder. It enables a user to input text and issue commands orally. The software in the computer converts the sound waves into digital form.

Q.19. What is the purpose of voice recognition system?

Ans : A voice recognition system coverts the speech of a person into digital data. It uses microphone as input device. It allows the user to use voice as input. It enables a user to input text and issue commands orally such as opening programs and using menus etc.

Q.20. What is light pen?

Ans : Light pen is a light-sensitive input‘ device. lts shape is similar to a traditional pen. It is used to draw on computer screen or select menus. lt is connected by a wire to the computer. It has a device at the tip that emits light. The pen sends information to the computer when user touches the pen on certain areas of a specially designed screen.

Q.21. What is digital camera?

Ans : Digital camera is an input device. ‘It stores images digitally in its memory rather than recording on film. The pictures taken with a digital camera can be downloaded on computer system. The pictures can be processed further with graphics programs. It does not require any film processing.

Q.22. Describe the use of disk drive.

Ans : A disk drive is used to read and write data on a disk. lt rotates the disk with precise timing. It has one or more read/ write heads to read and write data. The read/ write heads read data from disk and transfer it to main memory for further processing.

Q.23. Define output and its types.

Ans : The data that has been processed into useful information is called output. The output shown on display screen is called softcopy output. The output printed on paper is called hardcopy output.

Q.24. Define output devices.

Ans : The hardware components that are used to receive information from the computer are called output devices. Output devices take information from the computer and convert it in a form that is understandable by the users.

 

Q.25. Write names of some important output devices.

Ans : Some important output devices are-monitor, printer, plotter and speaker.

Q.26. What is the use of monitor?

Ans : The monitor is the most commonly used output device. It is also known as display or screen. The user looks at monitor while performing different tasks such as typing, issuing commands or surfing the Internet etc. An important factor that affects the quality of monitor is called resolution.

Q.27. List different types of monitors.

Ans : The different types of monitors are CRT monitor and flat panel monitor.

Q.28. What is CRT monitor?

Ans : CRT monitor is the most common form of monitor. It consists of a phosphorus coated screen. There are three electron guns on the back of screen. The phosphor coating of screen is organized into a grid of dots. The smallest number of phosphor dot that can be focused by the gun is called pixel.

Q.29. What is flat panel monitor?

Ans : Flat panel monitor is small in size. It takes less space and is light weight. It is usually used in portable computers and laptops. It uses less energy than CRT. It is more expensive than CRT monitor. The most common flat panel monitor is known as liquid crystal display (LCD) monitor.

Q.30. Differentiate between soft copy and hard copy.

Ans : Soft copy is in electronic form but hard copy is in printed form. Soft copy is easier to modify but hard copy is difficult to modify. Soft copy is stored on storage devices but hard copy is printed on paper. Soft copy can be duplicated without cost but hard copy can be duplicated with cost.

Q.31. Distinguish between CRT and LCD monitor.

Ans : CRT is less expensive than LCD monitor. lt takes more space and uses more energy than LCD. Its weight is more than LCD.

Q.32. What is video controller?

Ans : lt is a device between CPU and monitor. lt contains memory and circuitry to send information to monitor for display on screen. The resolution of monitor is actually determined by the video controller.

Q.33. Define printer.

Ans : A printer is an output device that prints characters, symbols and graphics on paper. The printed output is called hard copy. Print resolution is commonly measured in dots per inch (dpi). Printers are commonly used in businesses to print different documents.

Q.34. What are impact printers?

Ans : An impact printer works like-a typewriter. lt prints characters or images by striking a print hammer or set of pins against an inked ribbon. The ink is pressed from ribbon on the paper to produce the output. Impact printers are the oldest print technologies.

Q.35. What are non-impact printers?

Ans : A non-impact printer prints characters and graphics on paper without striking paper. Some printers use spray ink while others use heat and pressure to create images. These printers are faster than impact printer. The print quality of non-impact printers is better than impact printers.

Q.36. Differentiate between impact and non impact printer.

Ans : An impact printer prints characters or images by striking a print hammer or set of pins against an inked ribbon. A non-impact printer prints characters and graphics on paper without striking paper. The impact printers are slower than non impact printers. Non impact printers provide better output.

Q.37. List different impact printers.

Ans : Different impact printers are dot matrix printer, daisy wheel printer and line printer.

Q.38. Write the names of two non-impact printers.

Ans : Two examples of non-impact printers are inkjet printers and laser printers.

Q.39. How does a dot matrix printer work?

Ans : A dot matrix printer produces printed images when tiny pins on a print head strike an inked ribbon. When the ribbon presses against the paper, it creates dots that form characters and graphics. The print head on a dot matrix printer can contain nine to twenty-four pins.

Q.40. How does a laser printer work?

Ans : The laser printer is a non—impact printer. Its working is similar to photocopying machine. It uses laser beams to burn special ink on the page to create a permanent_ image. The ink is known as toner. Laser printer creates high quality output at higher speed. It does not make much noise.

Q.41. How does an inkjet printer work?

Ans : An ink-jet printer prints characters and graphics by spraying tiny drops of liquid ink on paper. These printers can produce quality text and graphics in both black-and-white and color including photos. A typical inkjet printer provides a resolution of 300 dots per inch.

Q.42. Compare inkjet and laser printers.

Ans : Laser printer provides high-quality text and graphics output. The price of inkjet printer is less than laser printer. Laser printers are faster than inkjet printers.

Q.43. Define pixel.

Ans : Pixel stands for picture element. Pixels are the dots that form images on the monitor. The higher number of pixels increases image sharpness.

Q.44. What is a plotter?

Ans : A plotter is a large scale printer. It receives commands from the computer to make drawings on paper. It creates output with one or more automatic pens. A plotter can draw continuous point-to-point lines from computer graphics files or commands. Plotters are much expensive than printers.

Q.45. Name different types of plotters.

Ans : Different types of plotters include drum plotter,- flat bed plotter and electrostatic plotter.

Q.46. What is CD-R?

Ans : CD-R stands for CD- recordable. The user can write data on CD-R only once but can read it many times. The data written to CD-R cannot be erased. CD-R can store 700MB of data. It is equal to 80 minutes of digital audio or video.

Q.47. What is CD-RW?

Ans : CD-RW stands for compact disc rewritable. The user can read and write data on CD-RW. CD Writer is used to store data on CD-RW disc. The user can write data_ on CD-RW many times by erasing the existing contents. Normally, the user can rewrite 1000 times on CD-RW.

Q.48. Differentiate between CD-R and CD-RW.

Ans : CD-R is used to write data only once and read it many times. The data written to CD-R cannot be erased. CD-RW is used to read and write data many times. Normally, the user can rewrite 1000 times on CD-RW.

 

Which of the following mouse event is used to view the properties of an object?



What type of printer forms images one character at a time as the print head moves across the paper?



Which of the following device is used to get hardcopy output?



 

Another name for pointer is:



 

Which of the following device is used to get hardcopy output?



 

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