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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 · 7 marks

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1Short recall1 markCharacter Sets Swap Remove

ASCII uses 7 bits to store each character. A system has only 6 bits available to store each character.

State the number of different characters the system can represent.

[1 mark]
Mark scheme

Award one mark for:

  • 64 (1)
  • 2^6 (1)
  • 2 × 2 × 2 × 2 × 2 × 2 (1)

Allow 64 characters / sixty-four.

Allow 2 to the power of 6 for 2^6.

Do not accept 128, which is the number of characters that can be represented using 7 bits.

Do not accept 63, the largest value that can be represented using 6 bits, rather than the number of different characters.

Do not accept 12 (2 × 6), ie the number of bits multiplied by 2.

Example answers and how they were marked
Full marks1/1

64

Why: Correct: 2^6 = 64 different characters (1).

No marks0/1

128

Why: Scores 0: 128 is the number of characters that 7 bits can represent, not the 6 bits the system has; the Do not accept line applies.

No marks0/1

63

Why: Scores 0: 63 is the largest value 6 bits can hold, not the number of different characters; the Do not accept line applies.

2Short recall2 marksImages Swap Remove

Bitmap images are stored as a grid of pixels.

Define the term pixel.

[2 marks]
Mark scheme

Award one mark for any of the following up to a maximum of two marks:

  • The smallest element/area of a bitmap image (1)
  • The smallest identifiable part of an image (1)
  • Stores/represents a single colour as a binary value (1)
  • Stores/represents a single colour using a number of bits/colour depth (1)

Allow 'picture element' for element/part in the first two bullets, but not on its own

Allow 'bit depth' for colour depth

Do not accept 'picture element'/'pixel' on its own

Do not accept 'a group of pixels' or 'a dot' on its own; allow 'dot' only when it is described as the smallest element/area of the image

Do not accept 'single colour' on its own for the second mark; it must be linked to a binary value/number of bits

Do not accept 'lots of coloured dots' (it contradicts a single colour)

Example answers and how they were marked
Full marks2/2

The smallest identifiable area of a bitmap image, which has one colour stored as a binary value.

Why: Smallest identifiable area (1) and single colour stored as a binary value (1)

Some marks1/2

The smallest part of a bitmap image, made of one colour.

Why: Smallest part (1); no credit for the second mark because the single colour is not linked to a binary value or number of bits

No marks0/2

A picture element made from lots of coloured dots.

Why: 'Picture element' on its own is not accepted and 'lots of coloured dots' contradicts a single colour

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 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

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 18 questions Intellectual Property 18 questions Software Licences 18 questions

5.3 Cybersecurity

Build a paper on this topic 36
Malware 18 questions Social Engineering 18 questions

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