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Representing images, sound and other data: AQA A‑Level Computer Science questions

Every AQA A-Level Computer Science exam question on 4.5.6 Representing images, sound and other data, 2020–2025, with its mark scheme and examiner’s report.

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561 questions

  1. Q02.1

    June 2025 · Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 Paper 2, question 02.1: A sound file, produced by sampling sound, requires 1.5 megabytes of storage space. The sound file has a duration of 50 seconds and was recorded at a sample rate

  2. Q02.2

    June 2025 · Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 Paper 2, question 02.2: Describe the principles of operation of an analogue to digital converter (ADC). [2 marks]

  3. Q02.3

    June 2025 · Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 Paper 2, question 02.3: Explain one reason why a digital sound file that has been recorded using sampling may not accurately represent the original analogue signal produced by the micr

  4. Q02.4

    June 2025 · Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 Paper 2, question 02.4: One advantage of representing a piece of music using MIDI instead of as sampled sound is that the file produced requires less storage space. Explain why. [2 mar

  5. Q10.1

    June 2025 · Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 Paper 2, question 10.1: State two reasons why data is often compressed. [2 marks] Reason 1 Reason 2

  6. Q10.2

    June 2025 · Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 Paper 2, question 10.2: Two different methods of compressing data are run length encoding (RLE) and dictionary-based methods. Explain why RLE is more suitable for compressing images an

  7. Q04.1

    June 2025 · AS Paper 2

    1 mark4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 AS Paper 2, question 04.1: Each time a sample of an analogue sound is taken a bit pattern is stored. Describe what each bit pattern represents. [1 mark]

  8. Q04.2

    June 2025 · AS Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 AS Paper 2, question 04.2: A sound file is being played on a laptop computer. The laptop contains a digital to analogue converter (DAC). Explain the role of the DAC and why it is necessar

  9. Q04.3

    June 2025 · AS Paper 2

    1 mark4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 AS Paper 2, question 04.3: A particular analogue sound must be sampled at a rate of at least 2200 Hz to be accurately represented. State the highest frequency present in the analogue soun

  10. Q05.1

    June 2025 · AS Paper 2

    1 mark4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 AS Paper 2, question 05.1: Explain why digital files are often stored in compressed format. [1 mark]

  11. Q05.2

    June 2025 · AS Paper 2

    1 mark4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2025 AS Paper 2, question 05.2: Run length encoding (RLE) can be used to compress data. Figure 2 shows some of the data from a file. Figure 2 BBGGGRRRRW State the RLE for the data shown in Fig

  12. Q02.1

    June 2024 · Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2024 Paper 2, question 02.1: A digital camera takes photographs that are 4000 pixels wide by 3000 pixels tall and can contain up to 16 777 216 different colours. Calculate the size of one i

  13. Q02.2

    June 2024 · Paper 2

    1 mark4.5.6 Representing images, sound and other data4.5.3 Units of information
    The whole paper ↗
    June 2024 Paper 2, question 02.2: How many images, taken using the camera referred to in Question 02.1, could be stored on a 256 gigabyte memory card? You should assume that all of the storage s

  14. Q02.3

    June 2024 · Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2024 Paper 2, question 02.3: Explain why the voltages produced by the photosensors are considered to be analogue and why the pixel data is considered to be digital. [2 marks]

  15. Q02.4

    June 2024 · Paper 2

    1 mark4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2024 Paper 2, question 02.4: Calculate how much memory the row of pixels will take up before and after it has been encoded using RLE. [1 mark] Memory before RLE (bytes) Memory after RLE (by

  16. Q02.5

    June 2024 · Paper 2

    1 mark4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2024 Paper 2, question 02.5: Comment on the effectiveness of the use of RLE to encode the row of pixels in Question 02.4 and explain why this is the case. [1 mark]

  17. Q03.1

    June 2024 · AS Paper 2

    1 mark4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2024 AS Paper 2, question 03.1: State the name of the component on a sound card that transforms the continuous signal received from a microphone to a form that can be stored by a computer. [1

  18. Q03.2

    June 2024 · AS Paper 2

    2 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2024 AS Paper 2, question 03.2: A bitmap image is 52 pixels in height and 26 pixels in width. The bitmap representation of the image requires 845 bytes. Calculate the maximum number of colours

  19. Q03.3

    June 2024 · AS Paper 2

    1 mark4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2024 AS Paper 2, question 03.3: When a bitmap image is stored in a file, additional information is stored as well as the colours of the pixels. For example, the bitmap file might contain infor

  20. Q03.4

    June 2024 · AS Paper 2

    3 marks4.5.6 Representing images, sound and other data
    The whole paper ↗
    June 2024 AS Paper 2, question 03.4: A sound is recorded with a sample rate of 96 000 Hz and a sample resolution of 24 bits. The file size of the recording is 12 096 kilobytes. A sample rate of 1 H
All 58 questions on Representing images, sound and other data, as a list
  1. June 2025, Paper 2, Q02.1 (2 marks): A sound file, produced by sampling sound, requires 1.5 megabytes of storage space. The sound file has a duration of 50 seconds and was recorded at a sample rate
  2. June 2025, Paper 2, Q02.2 (2 marks): Describe the principles of operation of an analogue to digital converter (ADC). [2 marks]
  3. June 2025, Paper 2, Q02.3 (2 marks): Explain one reason why a digital sound file that has been recorded using sampling may not accurately represent the original analogue signal produced by the micr
  4. June 2025, Paper 2, Q02.4 (2 marks): One advantage of representing a piece of music using MIDI instead of as sampled sound is that the file produced requires less storage space. Explain why. [2 mar
  5. June 2025, Paper 2, Q10.1 (2 marks): State two reasons why data is often compressed. [2 marks] Reason 1 Reason 2
  6. June 2025, Paper 2, Q10.2 (2 marks): Two different methods of compressing data are run length encoding (RLE) and dictionary-based methods. Explain why RLE is more suitable for compressing images an
  7. June 2025, AS Paper 2, Q04.1 (1 mark): Each time a sample of an analogue sound is taken a bit pattern is stored. Describe what each bit pattern represents. [1 mark]
  8. June 2025, AS Paper 2, Q04.2 (2 marks): A sound file is being played on a laptop computer. The laptop contains a digital to analogue converter (DAC). Explain the role of the DAC and why it is necessar
  9. June 2025, AS Paper 2, Q04.3 (1 mark): A particular analogue sound must be sampled at a rate of at least 2200 Hz to be accurately represented. State the highest frequency present in the analogue soun
  10. June 2025, AS Paper 2, Q05.1 (1 mark): Explain why digital files are often stored in compressed format. [1 mark]
  11. June 2025, AS Paper 2, Q05.2 (1 mark): Run length encoding (RLE) can be used to compress data. Figure 2 shows some of the data from a file. Figure 2 BBGGGRRRRW State the RLE for the data shown in Fig
  12. June 2024, Paper 2, Q02.1 (2 marks): A digital camera takes photographs that are 4000 pixels wide by 3000 pixels tall and can contain up to 16 777 216 different colours. Calculate the size of one i
  13. June 2024, Paper 2, Q02.2 (1 mark): How many images, taken using the camera referred to in Question 02.1, could be stored on a 256 gigabyte memory card? You should assume that all of the storage s
  14. June 2024, Paper 2, Q02.3 (2 marks): Explain why the voltages produced by the photosensors are considered to be analogue and why the pixel data is considered to be digital. [2 marks]
  15. June 2024, Paper 2, Q02.4 (1 mark): Calculate how much memory the row of pixels will take up before and after it has been encoded using RLE. [1 mark] Memory before RLE (bytes) Memory after RLE (by
  16. June 2024, Paper 2, Q02.5 (1 mark): Comment on the effectiveness of the use of RLE to encode the row of pixels in Question 02.4 and explain why this is the case. [1 mark]
  17. June 2024, AS Paper 2, Q03.1 (1 mark): State the name of the component on a sound card that transforms the continuous signal received from a microphone to a form that can be stored by a computer. [1
  18. June 2024, AS Paper 2, Q03.2 (2 marks): A bitmap image is 52 pixels in height and 26 pixels in width. The bitmap representation of the image requires 845 bytes. Calculate the maximum number of colours
  19. June 2024, AS Paper 2, Q03.3 (1 mark): When a bitmap image is stored in a file, additional information is stored as well as the colours of the pixels. For example, the bitmap file might contain infor
  20. June 2024, AS Paper 2, Q03.4 (3 marks): A sound is recorded with a sample rate of 96 000 Hz and a sample resolution of 24 bits. The file size of the recording is 12 096 kilobytes. A sample rate of 1 H
  21. June 2024, AS Paper 2, Q03.5 (1 mark): A sample resolution of 16 bits is commonly used in audio recordings. Explain why increasing the sample resolution from 16 bits to 24 bits can improve the qualit
  22. June 2024, AS Paper 2, Q03.6 (2 marks): MIDI does not use sampling to represent music. Describe how music is represented using MIDI. [2 marks]
  23. June 2024, AS Paper 2, Q03.7 (1 mark): Explain one advantage of using MIDI instead of sampled sound to represent music. [1 mark]
  24. June 2024, AS Paper 2, Q04.1 (1 mark): A message is encrypted using a Caesar cipher that operates with a shift value of four. For example, the letter A in plaintext would be represented by E in ciphe
  25. June 2024, AS Paper 2, Q04.2 (2 marks): Explain two reasons why Caesar ciphers are vulnerable to being cracked. [2 marks]
  26. June 2023, Paper 2, Q01.1 (2 marks): A sound is sampled and recorded digitally. The sound is sampled at a rate of 48 000 samples per second (Hz) for 3 minutes using a 16-bit sample resolution. Calc
  27. June 2023, Paper 2, Q01.2 (1 mark): The highest frequency component in a different sound is 15 000 Hz. What is the minimum sampling rate that should be used when recording this sound to ensure tha
  28. June 2023, Paper 2, Q01.3 (1 mark): Figure 1 shows part of the process of playing back a sound that has been sampled. The binary sound data is used to generate an electrical waveform. Figure 1 A h
  29. June 2023, Paper 2, Q03.1 (1 mark): Encrypt the plaintext SECURITY using the Caesar cipher with a key of 4. [1 mark] Plaintext Ciphertext SECURITY
  30. June 2023, Paper 2, Q03.2 (1 mark): State one weakness that both the Caesar cipher and the cipher shown in Figure 3 have which means they can be easily cracked. [1 mark]
  31. June 2023, Paper 2, Q03.3 (1 mark): State one reason why the cipher in Figure 3 is harder to crack than the Caesar cipher. [1 mark]
  32. June 2023, Paper 2, Q03.4 (2 marks): The Vernam cipher, unlike the Caesar cipher, can be perfectly secure. State two conditions that must be met for the Vernam cipher to offer perfect security. [2
  33. June 2023, AS Paper 2, Q05.1 (1 mark): Describe how to calculate the minimum storage requirements, excluding metadata, of a bitmapped image. [1 mark]
  34. June 2023, AS Paper 2, Q05.2 (1 mark): What is meant by the term sampling rate? [1 mark]
  35. June 2023, AS Paper 2, Q05.3 (1 mark): What is meant by the term sample resolution? [1 mark]
  36. June 2023, AS Paper 2, Q05.4 (2 marks): A sampled sound could be compressed using lossy compression. Describe a problem that may occur if lossy compression is used and how the compression method has c
  37. June 2023, AS Paper 2, Q05.5 (2 marks): An alternative to using sampled sound is MIDI. State two advantages of using MIDI instead of sampled sound. [2 marks]
  38. June 2022, Paper 2, Q10.1 (3 marks): A digital recording was made using a sampling rate of 44 100 Hz with a 16-bit sample resolution. A sampling rate of 1 Hz means that one sample has been taken ev
  39. June 2022, Paper 2, Q10.2 (3 marks): MIDI is a system that can be used to enable musical devices to communicate and to represent music on a computer. Describe the advantages of using MIDI to repres
  40. June 2022, AS Paper 2, Q04.5 (3 marks): The bit pattern 1000001 represents the character ‘A’ in 7-bit ASCII. Other characters follow on from this in sequence. For example, the bit pattern 1000100 repr
  41. June 2022, AS Paper 2, Q05.1 (2 marks): Describe the difference between analogue and digital data. [2 marks]
  42. June 2022, AS Paper 2, Q05.2 (3 marks): Describe the steps that an analogue to digital converter (ADC) carries out when converting a sound signal. [3 marks]
  43. June 2022, AS Paper 2, Q11 (12 marks): An international technology company produces a smart speaker for use in homes. The smart speaker can be controlled by a user providing voice commands, which mea
  44. November 2021, Paper 2, Q01.1 (3 marks): A bitmap image is 1000 pixels wide by 800 pixels high. The image takes up 400 kB of storage space when represented as a bitmap, excluding metadata. Calculate th
  45. November 2021, Paper 2, Q01.2 (3 marks): The same image can also be represented using vector graphics. The vector graphics representation of the image takes up 2 kB of storage space. Explain why the am
  46. November 2021, Paper 2, Q01.3 (2 marks): One advantage of vector graphics compared to bitmap graphics is that fewer bytes are used to represent an image. State two other advantages of vector graphics c
  47. November 2021, Paper 2, Q12 (2 marks): Describe how MIDI is used to represent digital music. [2 marks]
  48. November 2020, Paper 2, Q01.1 (2 marks): A sound has been sampled and recorded. The sound was sampled for 1 minute and 40 seconds at a sample rate of 8000 Hz with a 16-bit sample resolution. A sample r
  49. November 2020, Paper 2, Q01.2 (2 marks): An analogue to digital converter (ADC) was used during the sampling process. Explain the principles of operation of an ADC. [2 marks]
  50. November 2020, Paper 2, Q09.4 (3 marks): A message has been encrypted using the Caesar cipher with a key value of 5 Using the Caesar cipher, each capital letter is replaced by another capital letter (a
  51. November 2020, AS Paper 2, Q03.1 (3 marks): A sound is being recorded from an analogue source using a sound card in a computer. The sound card contains an analogue to digital converter (ADC). Describe the
  52. November 2020, AS Paper 2, Q03.2 (2 marks): Calculate the sample rate used for the recording. State your answer in samples per second (Hertz). You should show your working. [2 marks] Answer
  53. November 2020, AS Paper 2, Q03.3 (2 marks): State Nyquist’s theorem. [2 marks]
  54. November 2020, AS Paper 2, Q04 (2 marks): A student has attempted to calculate the minimum file size, in bytes, of a bitmapped image. The bitmapped image is 10 pixels wide by 16 pixels high with 4 possi
  55. November 2020, AS Paper 2, Q07.3 (1 mark): Another method of encryption is the Vernam cipher. Explain why, under the correct conditions, the Vernam cipher is perfectly secure. [1 mark]
  56. November 2020, AS Paper 2, Q09.1 (1 mark): State one reason why a user might choose to compress an image file. [1 mark]
  57. November 2020, AS Paper 2, Q09.2 (1 mark): Describe one advantage of lossless compression over lossy compression. [1 mark]
  58. November 2020, AS Paper 2, Q09.3 (3 marks): Explain how data can be compressed using dictionary-based compression. [3 marks]

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