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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 631 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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5 questions · 8 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

Each sample of a sound is stored as a binary number.

Describe how bit depth affects the stored value of a sound sample.

[2 marks]
Mark scheme

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

  • The bit depth is the number of bits used to store each sample/measurement (1) so a higher bit depth gives more possible/discrete values for the amplitude (1)
  • A higher bit depth records the amplitude more accurately (1) because the stored value can be closer to the actual height of the wave (1)
  • A low bit depth gives fewer possible amplitude values (1) so the amplitude is rounded to the nearest value, making the recording less accurate (1)

Do not accept sample rate/sample interval (number of samples per second) in place of bit depth.

Do not accept 'more bits gives better quality' or 'more accurate' on its own, without a development linked to the number of values or the amplitude stored.

Do not accept file size on its own, and a file size point cannot earn the second mark, as it does not describe the stored value.

Example answers and how they were marked
Full marks2/2

The bit depth is the number of bits used to store each sample, so a higher bit depth gives more possible values for the amplitude that can be stored.

Why: First point, the number of bits per sample (1), then the linked development, more possible values for the amplitude (1).

Some marks1/2

The bit depth is the number of bits used to store one sample.

Why: Gives the first point, the number of bits per sample (1), but does not develop how this affects the value that is stored.

No marks0/2

A higher bit depth makes the sound better quality and more accurate.

Why: Near-miss: 'better quality' and 'more accurate' on their own, with no development linked to the number of values or the amplitude, so no mark is awarded.

4Explain2 marksImages Swap Remove

A bitmap image uses a colour depth of 8 bits. Each pixel is stored as a binary value.

Explain how the colour of a pixel is represented in a bitmap image.

[2 marks]
Mark scheme

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

  • Each pixel is stored as a binary value/code (1) which represents/maps to a colour (1)
  • The binary value is used to look up a colour in a palette (1) so the pixel can be displayed in that colour (1)
  • A bit pattern is assigned to each colour (1) and each pixel stores the bit pattern for its colour (1)
  • The number of bits per pixel sets how many different colour codes exist (1) so each code can represent a different colour (1)

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

Do not accept 'pixels are binary' or 'the image is made of 1s and 0s' without saying a pixel's colour is represented by a binary value.

Do not accept RGB values stored as denary or hexadecimal.

Example answers and how they were marked
Full marks2/2

Each pixel stores a binary value (1); this value is used to look up the pixel's colour in a palette (1).

Why: Linked point (1) and reason (1): a binary value is stored for each pixel and maps to a colour.

Some marks1/2

A bit pattern is assigned to each colour.

Why: One mark for stating that colours have bit patterns; it does not say that each pixel stores the pattern for its colour.

No marks0/2

Each pixel stores the RGB colour as denary numbers between 0 and 255.

Why: Bitmap pixels are stored in binary, not as denary values; this common misconception earns no mark.

5Explain2 marksImages Swap Remove

An image uses a colour depth of 2 bits per pixel. The original image contains 12 different colours.

Explain why the image cannot be represented accurately at this colour depth.

[2 marks]
Mark scheme

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

  • Only 4 colours can be represented (1) because 2 bits give 2^2 = 4 possible values (1)
  • Some of the 12 colours cannot be stored (1) so they are lost/replaced with a colour that can be represented (1)
  • The image will not match the original exactly (1) because there are fewer colour codes than the number of colours needed (1)
  • Many colours will share the same binary value (1) so the image will lose colour detail (1)

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

Allow 'four colours' or '2^2'.

Do not accept 'only two colours' (confusing the number of bits with the number of values) or 'resolution is too low'.

Example answers and how they were marked
Full marks2/2

Only four colours can be represented (1) because two bits give four possible binary values (1).

Why: Linked point (1) and reason (1): 2 bits give 2^2 = 4 colour codes.

Some marks1/2

Only four colours can be represented.

Why: One mark for identifying that four colours can be represented; the linked reason about two bits giving four values is missing.

No marks0/2

Only two colours can be represented because each pixel has two bits.

Why: A common misconception: two bits give four possible values, not two, so no creditworthy point is given.

Questions by topic

2.1 Binary

Build a paper on this topic 58
Adding Binary Numbers 6 questions Binary and Hexadecimal Basics 10 questions Binary Shifts 6 questions Binary to Denary Conversion 6 questions Binary to Hexadecimal Conversion 6 questions Denary to Binary Conversion 6 questions Denary to Hexadecimal Conversion 6 questions Denary to Negative Binary Conversion 6 questions Hexadecimal to Binary Conversion 6 questions

2.2 Data representation

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Character Sets 18 questions Images 19 questions Sound 19 questions

2.3 Data storage and compression

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Compression 18 questions Units & Conversion 6 questions

3.1 Hardware

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Embedded Systems 17 questions Fetch Decode Execute Cycle 15 questions Primary Memory 15 questions Secondary Memory 15 questions Stored Program Computers 15 questions

3.2 Software

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File Management 18 questions Memory Management 16 questions Peripheral Management 11 questions Process Management 12 questions Purpose & Function of Operating Systems 17 questions Software Basics 13 questions User Management 18 questions Utility Software 19 questions

3.3 Programming languages

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Low and High Level Languages 19 questions Translators 18 questions

4.1 Networks

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Addressing 16 questions LANs & WANs 16 questions Network Speed 5 questions Packet Switching 16 questions Protocols & Layers 17 questions The Internet 16 questions Topologies 17 questions Wired Connections 17 questions Wireless Connections 18 questions

4.2 Network security

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Network Security Risks 18 questions Preventing Network Security Risks 18 questions

5.1 Environmental

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E-waste 17 questions Manufacturing Technology 19 questions

5.2 Ethical and legal

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Data Protection Act 17 questions Impact of AI 16 questions Intellectual Property 12 questions

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