Lesson 4.5.4.1

4.5.4.1 Unsigned binary Quiz: AQA Computer Science, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.5.4.1, Unsigned binary: 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 is the minimum value of an unsigned n-bit binary number?

    • 1
    • -(2^n - 1)
    • 0
    • -(2^(n-1))

  2. What is the maximum value of an unsigned n-bit binary number?

    • 2^(n-1) - 1
    • 2^n
    • 2^n - 1
    • n^2

  3. What distinguishes unsigned binary from signed binary?

    • Signed binary uses fewer bits than unsigned binary
    • Unsigned binary cannot represent negative numbers, while signed binary can
    • Unsigned binary stores fractions, while signed binary stores integers
    • Unsigned binary always uses 16 bits

  4. What is the largest value of an 8-bit unsigned binary number?

    • 256
    • 255
    • 128
    • 127

  5. Which 8-bit unsigned binary pattern represents 0?

    • 0000 0000
    • 1111 1111
    • 0000 0001
    • 1000 0000

  6. How many different values can unsigned n-bit binary represent?

    • 2^n
    • 2n
    • n^2
    • n

  7. Which 4-bit unsigned binary number represents decimal 9?

    • 1011
    • 1100
    • 0111
    • 1001

  8. Convert the unsigned binary number 1101 0110 to decimal.

    • 246
    • 212
    • 214
    • 218

  9. Convert the decimal number 200 to 8-bit unsigned binary.

    • 1100 1000
    • 1100 0100
    • 1001 1000
    • 1010 1000

  10. Add the unsigned 8-bit binary numbers 0110 1011 and 0001 1101. What is the result?

    • 0111 1000
    • 1000 1000
    • 1001 1000
    • 1000 0111

  11. What happens when 1111 + 0001 is added in 4-bit unsigned binary?

    • The result is 10000, which is stored in 4 bits because the adder keeps every bit that is produced
    • The result is 0000 with a carry out, because the true sum 16 does not fit in 4 bits
    • The result is 1111 with no carry, since the extra 1 is simply ignored by the adder circuit
    • The result is 0001, because the first number is unchanged and the second is discarded in the sum

  12. Multiply the unsigned binary numbers 101 and 11. What is the result?

    • 1101
    • 1111
    • 1110
    • 1011

  13. Convert the decimal number 45 to 8-bit unsigned binary.

    • 0010 1011
    • 0010 1101
    • 0101 1010
    • 0011 1100

  14. What is the decimal value of the 5-bit unsigned binary number 10110?

    • 22
    • 44
    • 20
    • 26

  15. A 3-bit unsigned counter starts at 000 and increments by 1 each time. What value does it show after 6 increments?

    • 111
    • 101
    • 100
    • 110

  16. Which decimal range can a 6-bit unsigned value represent?

    • 1 to 63
    • 0 to 31
    • 0 to 63
    • 0 to 64

  17. Why might adding two n-bit unsigned binary numbers need n+1 bits to store the result?

    • Carries are stored in an extra sign bit, so the sum always needs one more bit than the inputs
    • The result is always stored as a fraction of the operands, which needs an extra bit for the point
    • The sum can reach 2 x (2^n - 1), which may exceed the largest n-bit value 2^n - 1
    • Unsigned addition always doubles the number of bits used in every result that is stored

  18. How many bits are needed to store every unsigned whole number from 0 to 1000?

    • 8 bits, since 2^8 = 256 covers 1000 with spare values
    • 9 bits, since 2^9 = 512 covers 0 to 1000
    • 11 bits, since 2^11 = 2048 is needed for any value
    • 10 bits, since 2^10 = 1024 is the first power of two above 1000

  19. Multiply the unsigned 4-bit binary number 1111 by itself. What is the decimal result and the number of bits needed to store it?

    • 225, which needs 4 bits
    • 210, which needs 8 bits
    • 225, which needs 8 bits
    • 240, which needs 8 bits

  20. A 16-bit unsigned counter reaches 65535. Which statement is correct?

    • It is the minimum value for a 16-bit unsigned count
    • It is the maximum value, and one more increment gives 65536 in 16 bits
    • It equals 2^15, the midpoint of the 16-bit range
    • It is the maximum value, and one more increment wraps to 0 in 16 bits

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