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GCSE Computer Science (OCR)

Algorithms, programming, data, systems, networks. OCR board.

Pass mark 24/40 60 minutes OCR How many can I get wrong?
Sit a full mock under the clock at least once. Nerves are half the battle.
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Try 3 real GCSE Computer Science (OCR) questions
Have a go, then reveal the worked explanation. A taster from a bank of 212 original questions — unlock for unlimited drills and full timed mocks.
Q1. Which term describes breaking a large problem down into a series of smaller, more manageable sub-problems?
  • A.  Abstraction
  • B.  Decomposition
  • C.  Pattern recognition
  • D.  Backtracking
Show answer & explanation
✓ Answer: B. Decomposition
Decomposition is the process of splitting a complex problem into smaller sub-problems that are easier to solve individually. Abstraction is a different technique that involves removing unnecessary detail, not splitting the problem up.
Q2. A programmer declares an array: scores = [45, 67, 23, 89, 12]. What is the value of scores[2] if the array is zero-indexed, as in OCR's pseudocode?
  • A.  45
  • B.  67
  • C.  23
  • D.  89
Show answer & explanation
✓ Answer: C. 23
With zero-indexing the first element is scores[0], so scores[0]=45, scores[1]=67 and scores[2]=23. Students who mistakenly count from 1 often pick 67, which would only be correct under one-based indexing.
Q3. Why might an image using a higher colour depth still appear identical on screen to one using a lower colour depth, despite having a larger file size?
  • A.  Colour depth has no effect on file size at all
  • B.  If the original image only used a small range of colours to begin with, the extra colour depth adds no visible difference but still reserves more bits per pixel
  • C.  Higher colour depth always reduces file size
  • D.  Screens cannot display more than 16 colours regardless of colour depth
Show answer & explanation
✓ Answer: B. If the original image only used a small range of colours to begin with, the extra colour depth adds no visible difference but still reserves more bits per pixel
Colour depth sets the maximum number of colours that could be used per pixel, but if an image such as a simple black-and-white logo doesn't actually use that full range, increasing the colour depth still reserves more bits per pixel in storage without adding any visible detail. This illustrates why choosing an appropriate colour depth for the content matters for efficient storage.
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Algorithms & computational thinking · 35
Programming fundamentals · 37
Data representation & binary · 33
Computer systems & architecture · 35
Networks & security · 40
Ethical, legal & environmental issues · 32
GCSE Computer Science (OCR) — common questions
Frequently asked
How many questions are in the GCSE Computer Science (OCR)?
The exam has 40 questions. Every Revision Robin mock uses the same 40-question format so your practice matches the real thing.
What is the pass mark for the GCSE Computer Science (OCR)?
You need 24 out of 40 correct to pass, which is about 60%. Our mocks mark you against this exact threshold.
How long do you get?
The test is timed at 60 minutes. Our full mock runs on the same clock so you can practise your pacing.
Are these the real exam questions?
No. Our questions are original and written to match the current syllabus, so they give realistic practice without copying the official paper. Every answer comes with a plain-English explanation. Always confirm current rules and content with OCR.