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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 693 exam-style questions, each with its mark scheme and example answers. Print it, or answer it on paper and then open the mark schemes. Or browse the questions by topic.

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3 questions · 4 marks

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1Multiple choice1 markImages Swap Remove

Identify the term for the number of bits used to store the colour of each pixel.

[1 mark]
  • AColour depth
  • BImage size
  • CResolution
  • DStorage size
Mark scheme
  • A Colour depth (1)
  • The only correct answer is A. The correct answer is colour depth.
  • B is not correct because image size is the width and height of the image in pixels
  • C is not correct because resolution is the number of pixels per unit length, such as pixels per inch
  • D is not correct because storage size is the amount of storage the image file uses
Example answers and how they were marked
Full marks1/1

A Colour depth

Why: Correct option; colour depth is the number of bits used to store the colour of each pixel (1).

No marks0/1

B Image size

Why: Image size is the width and height of the image in pixels, not the number of bits used per pixel; no mark.

No marks0/1

D Storage size

Why: Storage size is the amount of storage the image file uses, not the colour depth; no mark.

2Short recall1 markCharacter Sets Swap Remove

ASCII uses 7 bits to store each character. A system has only 6 bits available to store each character.

State the number of different characters the system can represent.

[1 mark]
Mark scheme

Award one mark for:

  • 64 (1)
  • 2^6 (1)
  • 2 × 2 × 2 × 2 × 2 × 2 (1)

Allow 64 characters / sixty-four.

Allow 2 to the power of 6 for 2^6.

Do not accept 128, which is the number of characters that can be represented using 7 bits.

Do not accept 63, the largest value that can be represented using 6 bits, rather than the number of different characters.

Do not accept 12 (2 × 6), ie the number of bits multiplied by 2.

Example answers and how they were marked
Full marks1/1

64

Why: Correct: 2^6 = 64 different characters (1).

No marks0/1

128

Why: Scores 0: 128 is the number of characters that 7 bits can represent, not the 6 bits the system has; the Do not accept line applies.

No marks0/1

63

Why: Scores 0: 63 is the largest value 6 bits can hold, not the number of different characters; the Do not accept line applies.

3Explain2 marksImages Swap Remove

Two versions of the same bitmap image are saved. The second version has a higher colour depth.

Explain why the second version may have a larger file size.

[2 marks]
Mark scheme

Award up to two marks for a linked explanation such as:

  • More binary data is stored for each pixel (1) because a higher colour depth uses more bits per pixel (1)
  • Each pixel has a longer binary code (1) so more storage is needed to hold the image (1)
  • More colours can be represented (1) so more bits are needed for each pixel (1)
  • The file contains more bits in total (1) because colour depth is the number of bits per pixel (1)

For both marks, the expansion must follow/associate with the statement.

Allow 'more bits per pixel' for one mark.

Do not accept 'more pixels' or 'higher resolution' as the reason, because changing colour depth does not change the number of pixels.

Example answers and how they were marked
Full marks2/2

The second version stores more binary data for each pixel because a higher colour depth uses more bits per pixel.

Why: Linked point (1) and reason (1): more data per pixel because more bits per pixel.

Some marks1/2

The second version uses more bits for each pixel.

Why: One mark for identifying that more bits are stored per pixel; no linked statement about more data or file size.

No marks0/2

The second version has more pixels, so there is more data to store.

Why: A common misconception; colour depth does not change the number of pixels, so no creditworthy point is given.

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