Lesson 4.5.6.1

4.5.6.1 Bit patterns for images, sound and other data Quiz: AQA Computer Science, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.5.6.1, Bit patterns for images, sound and other data: 20 multiple choice questions for the AQA Computer Science (7517), Unit 5: Fundamentals of data representation, written with Revision Ninja.

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The 20 questions

  1. What does a bit pattern represent in a computer?

    • Only machine instructions, which the processor decodes one at a time from the memory store
    • A fixed type of data that cannot change, so every pattern always means the same thing
    • Only numbers written in binary form, which are read directly as integers by the processor
    • Any data, such as a number, character, image or sound, depending on how it is interpreted

  2. Why can the same bit pattern mean different things?

    • Its value changes each time it is read, so the same bits can give a different answer
    • Bit patterns always store the same type of data, so the meaning never depends on the reader
    • Bit patterns are random and have no meaning until they are chosen by the user at random
    • Its meaning depends on the data type or program that interprets it

  3. How is the colour of a bitmap pixel typically stored?

    • As a single ASCII character that identifies the colour by its code in the table
    • As a sampling frequency in hertz, which gives the number of colours per second
    • As a list of geometric shapes, each with its own coordinates and a fill colour value
    • As a bit pattern whose length is the colour depth

  4. How is a sound sample stored in digital form?

    • As the frequency of the sound in hertz only, with no record of the level at each moment
    • As a binary number representing the amplitude of the sound at one moment
    • As a list of geometric shapes, each defined by its coordinates and drawing properties
    • As a decimal string of pixel coordinates, with one string for each sample of the sound

  5. Which of these is a bit pattern used to represent a character?

    • The ASCII code 65 for the letter 'A'
    • The image resolution of 300 dpi
    • The frame count of a video
    • The sampling rate of 44.1 kHz

  6. What do the 0s and 1s of a machine instruction represent?

    • Patterns of bits that the processor decodes as operations
    • Random data used only for padding the file, so that it reaches a fixed block size
    • A list of geometric objects that the processor draws onto the screen as shapes
    • Human-readable words stored as ASCII text, which the processor translates into operations

  7. How many distinct patterns can an 8-bit byte represent?

    • 128
    • 256
    • 8
    • 64

  8. A 4-bit colour depth is used for each pixel. How many colours can each pixel show?

    • 4
    • 256
    • 8
    • 16

  9. A pixel's 24-bit RGB pattern is FF 00 00 in hexadecimal. What colour is shown?

    • Red
    • Black
    • Blue
    • Green

  10. A pixel's 24-bit RGB pattern is 00 FF 00 in hexadecimal. What colour is shown?

    • Green
    • White
    • Red
    • Blue

  11. The byte 01000001 is read as an unsigned integer and as an ASCII character. Which pair is correct?

    • 66 and 'B'
    • 97 and 'a'
    • 67 and 'C'
    • 65 and 'A'

  12. The byte pattern 0101 1010 is read as a hexadecimal value. What is it?

    • 50
    • 5B
    • 5A
    • A5

  13. A 1-bit image has pixels with bits 1, 0, 1, 1, where 1 is black. How many pixels are black?

    • 1
    • 3
    • 2
    • 4

  14. A 16-bit sound sample can take how many distinct amplitude levels?

    • 256
    • 32,768
    • 65,536
    • 16

  15. A single byte 11111111 is read as a grey-scale intensity from 0 (black) to 255 (white). What is shown?

    • An invalid value
    • White
    • Mid grey, at 128
    • Black

  16. Convert the decimal number 1000 to a 16-bit unsigned bit pattern.

    • 0000 0100 0000 0000
    • 0000 0011 1110 1000
    • 0000 1111 1110 1000
    • 0000 0011 1110 0100

  17. Why does it matter which data type a 16-bit pattern is read as?

    • The machine converts the pattern automatically to the correct type whenever it is read from memory
    • Reading with the wrong data type gives a meaningless value, so the type must be known to interpret the bits
    • The pattern changes according to the data type when it is stored, so its value is recalculated
    • Interpretation never affects the result, because each set of bits carries its own fixed meaning

  18. A byte 10000000 is read as a signed two's complement value and as an unsigned value. Which pair is correct?

    • -128 signed and 128 unsigned
    • -1 signed and 255 unsigned
    • 128 signed and -128 unsigned
    • 0 signed and 128 unsigned

  19. Why can a file store a bit pattern without it being image or sound data?

    • Only image files may store bit patterns, so any other kind of file is treated as invalid data
    • A file is a sequence of bytes, and the software and file format decide what those bytes mean
    • Bit patterns become images only when a printer reads them, so the file is printed as shapes
    • The operating system converts all bytes into ASCII text whenever a file is opened for reading

  20. An image uses 8-bit colour indexing. What is needed to find the colour that an index represents?

    • The file's header timestamp, which records when each colour index was last changed
    • A palette table that maps each index to a colour value
    • The pixel's sign bit, which decides whether the colour index is read as positive or negative
    • The pixel's sampling rate, which tells the display how fast each colour index should be read

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