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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 659 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 · 5 marks

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1Short recall2 marksCharacter Sets Swap Remove

ASCII is a character set that uses 7 bits to represent each character.

Give two limitations of 7-bit ASCII when it is used to represent text.

[2 marks]
Mark scheme

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

  • (Only) 128 different characters can be represented / 7 bits give 2^7 = 128 different codes (1)
  • It cannot represent characters from languages other than English / non-English alphabets, e.g. Greek, Chinese (1)
  • It cannot represent accented characters, e.g. é, ñ (1)
  • It cannot represent symbols or emoji that are not in the ASCII character set (1)

Award a maximum of one mark for the last three bullets, as they are all examples of characters that fall outside the 128 ASCII codes.

Allow 'it can only represent 128 characters, so some characters are missing' for the first bullet.

Do not accept 'it uses 7 bits' / 'it only uses 7 bits' on its own, without saying what this limits.

Do not accept 'it can only store a limited amount of text' / 'it can only store short messages', as 7 bits limits the number of characters available, not the length of a message.

Do not accept 'it can only represent the characters in the ASCII character set', as this repeats the question.

Do not accept 'it is old/out of date' or 'it cannot store numbers'.

Example answers and how they were marked
Full marks2/2

Only 128 different characters can be represented, so it cannot store characters from other languages such as Greek.

Why: 128 character limit (1) and characters from other languages (1); two separate creditworthy limitations.

Some marks1/2

It cannot show accented characters like é and it only uses 7 bits.

Why: Accented characters (1); 'only uses 7 bits' is not qualified, so scores 0.

No marks0/2

It only uses 7 bits, so it can only store a small amount of text.

Why: Scores 0: text length is not a limitation of 7-bit ASCII, and 'only uses 7 bits' is unqualified; both Do not accept lines apply.

2Short 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.

3Describe2 marksSound Swap Remove

Sound is converted into binary using a limited bit depth.

Describe one limitation of representing a sound sample with a limited bit depth.

[2 marks]
Mark scheme

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

  • Only a fixed number of amplitude values/levels can be represented (1) so the amplitude is rounded to the nearest available value/level (1)
  • Fewer amplitude values/levels are available to choose from (1) so similar/close amplitudes cannot be stored as different values (1)
  • The exact amplitude often falls between available values/levels (1) so the stored amplitude is not exact/less accurate (1)

Answers must relate to the number of bits per sample (bit depth) and the amplitude values/levels it can represent.

Do not accept answers about the sample rate, sample interval or the number of samples taken, or that confuse bit depth with the number of samples.

Do not award 'lower quality'/'more detail'/'less detail' unless it is linked to the number of amplitude values/levels.

Do not accept 'the sound cannot be played/stored' without a linked limitation.

Example answers and how they were marked
Full marks2/2

Only a fixed number of amplitude values can be represented, so the amplitude is rounded to the nearest available value and some detail is lost.

Why: Linked points: fixed number of amplitude values (1) and rounding to the nearest available value (1).

Some marks1/2

Only a fixed number of amplitude values can be represented.

Why: Gives the first linked point only (1); it does not develop what this limitation leads to.

No marks0/2

A lower bit depth means fewer samples are taken, so parts of the sound are missed.

Why: Confuses bit depth with the number of samples/sample rate; no creditworthy point about amplitude values 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 18 questions Intellectual Property 18 questions Software Licences 12 questions

5.3 Cybersecurity

Malware 8 questions

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