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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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4 questions · 6 marks

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1Multiple choice1 markImages Swap Remove

Identify the smallest identifiable area of a bitmap image.

[1 mark]
  • AColour depth
  • BFile size
  • CPixel
  • DResolution
Mark scheme
  • C Pixel (1)
  • The only correct answer is C. The correct answer is pixel.
  • A is not correct because colour depth is the number of bits used to store the colour of each pixel
  • B is not correct because file size is the amount of storage an image takes up, not an area of the image
  • D is not correct because resolution is a measure of the number of pixels in an image (such as its width × height), not the smallest identifiable area
Example answers and how they were marked
Full marks1/1

C Pixel

Why: Correct option; a pixel is the smallest identifiable area of a bitmap image (1).

No marks0/1

D Resolution

Why: Resolution is a measure of the number of pixels in an image, not the smallest identifiable area; no mark.

No marks0/1

A Colour depth

Why: Colour depth is the number of bits used to store each pixel's colour, not the smallest identifiable area; no mark.

2Short recall1 markImages Swap Remove

A bitmap image uses one bit per pixel.

State the limitation this places on the number of colours in the image.

[1 mark]
Mark scheme

Award one mark for any of the following:

  • Only two different colours can be represented/stored (1)
  • Each pixel can only be one of two values (1)
  • The image can only be shown in black and white (1)

Allow answers that give the number of colours, e.g. two colours, 2 colours

Allow any pair of two colours, e.g. black and white, black and grey

Do not accept low resolution/poor quality/lower quality

Do not accept only one colour/can only show black

Do not accept 2 bits/2^1 without a statement about the number of colours that can be represented

Example answers and how they were marked
Full marks1/1

Only two colours can be represented, such as black and white.

Why: States that only two different colours can be represented (1)

No marks0/1

The image will have a low resolution.

Why: Confuses colour depth with resolution; low resolution is not accepted

No marks0/1

The image can only show black.

Why: One colour is all a single value can give; the limitation is that only two colours can be represented, so this is not accepted

3Describe2 marksCharacter Sets Swap Remove

A school needs to store text in several different languages.

Describe one limitation of using 7-bit ASCII to store this text.

[2 marks]
Mark scheme

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

  • 7-bit ASCII has only 128 different codes (1) so characters from languages such as Chinese cannot be stored (1)
  • 7 bits give 2^7 = 128 possible binary codes (1) so there are not enough codes to give every character in the world's languages its own code (1)
  • Only the 128 characters in the ASCII set can be stored (1) so a character outside the set, such as é or 中, cannot be represented (1)

The stated limit on its own (that ASCII can represent only 128 characters) earns 1 mark; the second mark is for linking it to characters from other languages not being storable.

Do not accept 'ASCII can only store English letters/characters' unless it refers to the 128 codes or the 7 bits.

Do not accept a statement that ASCII is 'limited' or 'old' with no link to the number of bits/codes.

Do not accept a recommendation to use Unicode instead, or that ASCII cannot store accented letters, without saying that the 7 bits/128 codes cause the limitation.

Do not accept responses that describe ASCII as a programming language.

Example answers and how they were marked
Full marks2/2

7-bit ASCII can only represent 128 characters, so it cannot store characters from languages such as Chinese.

Why: Only 128 characters/codes can be represented (1) and this is linked to characters from other languages not being storable (1).

Some marks1/2

ASCII only has 128 characters.

Why: States the limit set by the 7 bits, that only 128 characters can be represented (1), but does not link it to the text in several languages (0).

No marks0/2

ASCII can only store English letters, so the school should use Unicode to store accented letters like e with an accent.

Why: 'Only stores English letters' is not accepted without reference to the 128 codes/7 bits, and recommending Unicode is not a limitation caused by the number of available bits.

4Explain2 marksImages Swap Remove

Two versions of the same photograph are displayed at the same size on a screen. Version A is 800 × 600 pixels. Version B is 1600 × 1200 pixels.

Explain why Version B can show more detail.

[2 marks]
Mark scheme

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

  • Version B has more pixels in the same area (1) so each pixel represents a smaller part of the image (1)
  • Version B has a higher pixel density (1) so finer detail can be represented (1)
  • The pixels in Version B are smaller (1) so more detail can be captured in the same space (1)
  • Version B has a higher resolution (1) because there are more pixels per unit of area (1)

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

Do not accept 'more pixels' on its own without saying same area/pixel density/smaller pixels.

Do not accept higher colour depth or more colours.

Example answers and how they were marked
Full marks2/2

Version B has more pixels in the same area so each pixel represents a smaller part of the image.

Why: Linked point (1) and reason (1): more pixels in the same area means smaller pixels and more detail.

Some marks1/2

Version B has more pixels in the same area.

Why: One mark for the point about pixel density; the linked reason about smaller pixels or finer detail is missing.

No marks0/2

Version B has a higher colour depth, so it can display more colours.

Why: Colour depth is not the reason for more detail here; this is the common misconception that colour depth increases resolution.

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