Lesson T4.3.1

T4.3.1 Representing text, sound and pictures digitally Quiz: KS3 Computing, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson T4.3.1, Representing text, sound and pictures digitally: 20 multiple choice questions for the KS3 Computing (National Curriculum), Unit 4: Computer systems, written with Revision Ninja.

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The 20 questions

  1. Why do computers use binary to represent all data?

    • Simple typing
    • Small file size
    • Two reliable states
    • Maximum speed

  2. How many bits are there in one byte?

    • 10
    • 4
    • 8
    • 16

  3. How many different values can 4 bits represent?

    • 8
    • 32
    • 4
    • 16

  4. What does ASCII encode text characters into?

    • Sound waves
    • Vector shapes
    • Colour values
    • Binary numbers

  5. Which character set supports multiple global languages and symbols?

    • Boolean
    • Binary
    • ASCII
    • Unicode

  6. A bitmap image is 100 pixels wide and 50 pixels high, and each pixel uses 8 bits. How many bits does the image need?

    • 40,000 bits
    • 400 bits
    • 80,000 bits
    • 5,000 bits

  7. What determines the quality and detail of a bitmap image?

    • Bit depth
    • Sample rate
    • Frequency
    • Resolution

  8. What is the number of bits per pixel in an image called?

    • Sample rate
    • Colour depth
    • File size
    • Image resolution

  9. What measures how many times per second a sound wave is recorded?

    • Bit depth
    • Amplitude
    • Sampling rate
    • Frequency

  10. A mono sound lasts 10 seconds, is sampled 1,000 times per second, and each sample uses 8 bits. How many bits does it need?

    • 80,000 bits
    • 10,000 bits
    • 800,000 bits
    • 8,000 bits

  11. What increases when you raise the bit depth of a digital sound recording?

    • Volume precision
    • Playback speed
    • Sample rate
    • File compression

  12. What type of data must be converted before a computer can store sound?

    • Binary
    • Vector
    • Digital
    • Analogue

  13. Which type of image uses mathematical shapes to scale without losing quality?

    • Vector image
    • Bitmap image
    • JPEG photo
    • Raster graphic

  14. What type of compression permanently removes some data to reduce file size?

    • Lossless compression
    • Binary compression
    • Lossy compression
    • Vector compression

  15. How are individual text characters stored inside a computer system?

    • Compressed pixels
    • Binary codes
    • Mathematical vectors
    • Analogue waves

  16. What is the denary value of the binary number 1010?

    • 10
    • 14
    • 12
    • 8

  17. Which unit is the largest of these?

    • Byte
    • Megabyte
    • Gigabyte
    • Kilobyte

  18. What causes a digital photograph file to have a large size?

    • Low colour depth
    • Lossy compression
    • High resolution
    • Small dimensions

  19. What structure is used to store a standard digital bitmap picture?

    • Waveform graph
    • Pixel grid
    • Logic gate
    • Vector path

  20. Which image format uses lossless compression?

    • MPEG
    • MP3
    • PNG
    • JPEG

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