IGCSE Computer Science Paper 1 Definitions Worksheet: 3.2 Input and Output Devices (Modules 262–272)
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Date:
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Key terms
Write what each term means, in your own words.
1
suitable input device
2
LCD screen
3
LED screen
4
LCD vs LED
5
LCD projector
6
DLP projector
7
LCD vs DLP
8
Inkjet printer
9
laser printer
10
inkjet vs laser
Answer Key
IGCSE Computer Science Paper 1 · Modules 262–272 · Student wording will vary for definitions
1suitable input device — The input device that best captures the data needed and suits the user's situation. Justify it with 'because'. E.g. a microphone because it captures sound.
2LCD screen — Screen with a backlight shining through liquid crystals that twist to block or pass light. Red, green and blue filters on each pixel make its colour.
3LED screen — A screen that uses light emitting diodes as its light source, as a backlight for an LCD panel or as the pixels themselves. It is bright, thin and uses little power.
4LCD vs LED — LCD screens use a fluorescent (CCFL) backlight; LED screens use LED backlights, so they are brighter, thinner, have better contrast and use less power.
5LCD projector — An output device: a bright lamp shines light through red, green and blue LCD panels that form the image, then a lens focuses the recombined light onto a screen.
6DLP projector — A projector with a chip of tiny mirrors (one per pixel) that tilt towards or away from the lens to make the image. A spinning colour wheel adds colour.
7LCD vs DLP — Both projectors show an image on a screen. LCD shines light through liquid crystal panels; DLP bounces light off tiny mirrors (micromirrors). They differ in sharpness, colour, size and cost.
8Inkjet printer — Sprays tiny droplets of liquid ink through nozzles in a print head onto paper as the head moves across it. Uses cyan, magenta, yellow and black cartridges.
9laser printer — A printer that uses a laser to draw the image as static charge on a drum. Toner sticks to the charged areas, is transferred to paper, then fixed by a heated fuser.
10inkjet vs laser — Inkjet sprays liquid ink: good photo quality, cheap to buy, costly per page. Laser fuses toner powder: fast, sharp text, dearer to buy, cheaper per page.