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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 markSound Swap Remove

Digital sound is made up of samples.

Define the term 'bit depth'.

[1 mark]
Mark scheme

Award one mark for:

  • The number of bits used per sample (1)

Allow bits per sample

Allow the number of bits used to record/store each sample

Do not accept the number of samples taken per second (sample rate)

Do not accept the number of bits used to store the whole sound file

Do not accept the number of levels/amplitude values a sample can take

Example answers and how they were marked
Full marks1/1

The number of bits used to record each sample.

Why: States the number of bits per sample (1).

No marks0/1

The number of samples taken each second.

Why: Defines sample rate, not bit depth; do not accept.

No marks0/1

The number of amplitude values each sample can take.

Why: Gives the number of levels/amplitude values, not the number of bits per sample; do 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 marksSound Swap Remove

An analogue sound wave is sampled and stored as binary.

Describe how the amplitude of the sound wave is represented in binary.

[2 marks]
Mark scheme

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

  • The height of the wave is measured at each sample (1) and stored as a binary value (1)
  • The amplitude at a sample point is converted into a binary number using the bit depth (1) so each sample stores the height of the wave (1)
  • A larger amplitude is stored as a larger binary value (1) so louder parts of the sound are represented by higher values (1)

Do not accept answers that only define amplitude as the height/loudness of the wave.

Do not accept answers about the number of samples taken each second (sample rate).

Example answers and how they were marked
Full marks2/2

The height of the wave is measured at each sample point and this height is stored as a binary number.

Why: Gives the linked points: amplitude measured at each sample (1) and stored as a binary value (1).

Some marks1/2

The amplitude is measured at each sample.

Why: Gives the first point, measurement at each sample (1), but does not link it to being stored as a binary value.

No marks0/2

The amplitude is the number of samples taken every second.

Why: Confuses amplitude with sample rate; neither creditworthy point is given.

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