Menu

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.

Build a paper

Topics (none ticked: all of them)
Question types (none ticked: all of them)

Practice paper

3 questions · 4 marks

Pick again
Print
1Multiple choice1 markSound Swap Remove

Identify the term used for the number of bits used to record each sample of a sound.

[1 mark]
  • AAmplitude
  • BBit depth
  • CSample interval
  • DSample rate
Mark scheme
  • B Bit depth (1)
  • The only correct answer is B. The correct answer is bit depth.
  • A is not correct because amplitude is the height of the sound wave at the point it is sampled
  • C is not correct because the sample interval is the time between each sample
  • D is not correct because the sample rate is the number of samples taken each second
Example answers and how they were marked
Full marks1/1

B Bit depth

Why: Selects the only correct option (1).

No marks0/1

D Sample rate

Why: Near miss: this is the number of samples taken each second, not the number of bits per sample (0).

No marks0/1

A Amplitude

Why: Typical confusion: amplitude is what is measured at a sample, not the number of bits used to store it (0).

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

3Explain2 marksCharacter Sets Swap Remove

ASCII uses a fixed number of bits to represent each character.

Explain one reason why ASCII uses 7 bits to represent each character.

[2 marks]
Mark scheme

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

  • 7 bits give 128 different codes/combinations (1) which is enough to represent all the characters on a keyboard (1)
  • 7 bits allow 128 unique characters (1) so uppercase and lowercase letters, digits and punctuation can all be represented (1)
  • 6 bits give only 64 combinations (1) which is not enough for the number of characters on a keyboard (1)
  • A keyboard needs to represent more than 64 different characters (1) so 7 bits are needed to give the 128 combinations required (1)
  • A fixed number of 7 bits gives 128 possible codes (1) which is enough for the characters ASCII represents, so more bits are not needed (1)

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

Do not accept 'because ASCII is 7-bit' or 'because 7 bits is enough' as these repeat the question without giving the number of combinations or saying what they allow.

Do not accept '7 bits give 256 characters'; 256 combinations come from 8 bits (extended ASCII).

Allow 'ASCII has 128 characters/codes' for the 128 point.

Example answers and how they were marked
Full marks2/2

7 bits give 128 different codes, which is enough for every letter, digit and punctuation symbol on a keyboard.

Why: Gives the point that 7 bits give 128 codes (1) and links it to the reason that this is enough for all the characters on a keyboard (1).

Some marks1/2

7 bits give 128 different combinations.

Why: Gives the point that 7 bits give 128 combinations (1) but does not say what this number of combinations allows, so the linked reason (1) is not earned.

No marks0/2

Because ASCII uses 7 bits so it can store 256 characters.

Why: Repeats the question and gives the wrong number of characters (256 is 8-bit extended ASCII), so there is no creditworthy point.

Questions by topic

More ways to revise Edexcel GCSE Computer Science (1CP2)

Teachers: build a paper, print it with the mark schemes at the end, and sign your school up to set your classes activities on every topic.

Fetch Decode Explain isn't affiliated with or endorsed by Pearson Edexcel.