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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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1Short recall1 markImages Swap Remove

Each pixel in a bitmap image is stored using a number of bits.

Define the term colour depth.

[1 mark]
Mark scheme

Award one mark for any of the following:

  • The number of bits per pixel (1)
  • The number of bits used to represent/store the colour of each pixel (1)

Allow bit depth

Do not accept the number of colours a pixel can have on its own

Do not accept the number of pixels in the image (this is the resolution/image size)

Example answers and how they were marked
Full marks1/1

The number of bits used to store the colour of one pixel.

Why: Gives the number of bits per pixel (1)

No marks0/1

The number of colours that each pixel can use.

Why: Gives the number of colours, not the number of bits; the mark scheme does not accept this on its own

No marks0/1

The number of pixels in the image.

Why: Confuses colour depth with resolution/image size, which the mark scheme does not accept

2Short recall1 markImages Swap Remove

A bitmap image has a resolution.

State what is meant by the resolution of an image.

[1 mark]
Mark scheme

Award one mark for any of the following:

  • The concentration/density of pixels in an area (1)
  • The number of pixels per inch (PPI) / pixels per unit area (1)
  • The width and height/dimensions of the image in pixels (1)

Do not accept the number of pixels in the image on its own, without dimensions or an area, e.g. 'the total number of pixels'

Do not accept colour depth / the number of bits used per pixel / the number of colours

Do not accept file size in bytes / the amount of storage the image uses / screen size / image quality

Example answers and how they were marked
Full marks1/1

The concentration of pixels in an area, such as the number of pixels per inch.

Why: Gives the density/concentration of pixels in an area, and pixels per inch (1)

No marks0/1

The number of pixels in the image.

Why: A bare total pixel count is not accepted without dimensions or an area

No marks0/1

The number of bits used to store each pixel's colour.

Why: Describes colour depth, not resolution, and colour depth is not accepted

3Describe2 marksCharacter Sets Swap Remove

Uppercase letters are represented in a computer using 7-bit ASCII codes.

Describe how the ASCII codes for the uppercase letters A to Z are arranged.

[2 marks]
Mark scheme

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

  • The codes run in alphabetical order/consecutively (1) so each letter has a code one more than the letter before it (1)
  • A has the code 65 and Z has the code 90 (1) so the codes for the letters in between increase by 1 each time (1)
  • The letters are stored in sequence (1) so B is A + 1, C is B + 1 and so on (1)

Accept the codes given in denary (65, 90) or as 7-bit binary (1000001, 1011010).

Do not accept 'the codes go up' or 'the codes are in order' on its own, as neither gives the step of 1 or links one letter to the next.

Do not accept 'each uppercase letter has a different code' on its own, as this does not describe the arrangement.

Example answers and how they were marked
Full marks2/2

The codes are in alphabetical order, so B is one more than A and C is one more than B.

Why: Codes are consecutive/in order (1) with the linked step of one more for each letter (1).

Some marks1/2

A is 65 and Z is 90.

Why: Gives the first half of the linked pair, the start and end codes (1), but does not give the linked development, the increase of 1 between letters (0).

No marks0/2

The ASCII codes for uppercase letters go up.

Why: 'Codes go up' on its own gives no step of 1 and no link to the next letter, so it is not creditworthy (0) under the 'Do not accept' line.

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