Which of the following is both an input and an output device?
- A.Scanner
- B.Plotter
- C.Touchscreen
- D.Light pen
Correct answer
Explanation
The correct answer is C, touchscreen. A touchscreen accepts a finger tap or a stylus stroke as input and displays the result on the very same surface, so the one piece of hardware performs both jobs. The modem, the network interface card and the hard disk belong to the same dual-role list.
Option A, the scanner, only reads a document or a photograph and feeds the image into the computer, which makes it a pure input device. Option B, the plotter, only draws the output the computer sends it and can take nothing back, so it is a pure output device. Option D, the light pen, is a photo-sensitive pointing device that selects an item by touching the screen, but the display it touches is a separate output device, so the pen itself is input only. Paper setters use exactly these three distractors, so remember the short dual-role list rather than reasoning about each option in the hall.
Read the full article: Input and Output Devices: Types, Examples and MCQs
Practice Questions
View allWho invented the computer mouse?
- A.Douglas Engelbart
- B.Charles Babbage
- C.Jack Kilby
- D.Christopher Latham Sholes
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He built the first mouse, a small wooden box with a pair of wheels underneath, at the Stanford Research Institute, and the patent describes it as an X-Y position indicator for a display system.
Read the full explanation →Which of the following is an impact printer?
- A.Laser printer
- B.Inkjet printer
- C.Dot matrix printer
- D.Thermal printer
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Its print head carries a column of tiny pins that strike an inked ribbon against the paper, forming each character out of dots.
Read the full explanation →MICR technology is used mainly in which of the following?
- A.Processing of bank cheques
- B.Reading objective answer sheets
- C.Billing at a retail counter
- D.Recording fingerprints
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MICR stands for Magnetic Ink Character Recognition. The line of characters printed along the foot of a cheque is set in magnetic ink in the E-13B font, and the reader identifies each character from its magnetic signal, so the cheque is sorted correctly even when it has been folded, stamped…
Read the full explanation →The smallest element of a picture displayed on a computer screen is called a
- A.Bit
- B.Pixel
- C.Byte
- D.Dot pitch
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The word is a contraction of picture element. A screen image is a grid of these points, and the number of them across and down the screen is what is quoted as the resolution of the monitor, so a higher pixel count means a finer picture.
Read the full explanation →The print quality of a printer is measured in which unit?
- A.PPM
- B.CPS
- C.DPI
- D.LPM
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Print quality depends on how many separate dots of ink or toner the printer can place in one inch of paper, so a printer working at a higher DPI produces smoother curves and crisper small text.
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