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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 · 8 marks

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1Short recall2 marksCharacter Sets Swap Remove

A computer uses a character set to represent text.

Define the term character set.

[2 marks]
Mark scheme

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

  • A set/collection of characters (1)
  • (Characters such as) letters, digits and symbols/punctuation (1)
  • Each character is represented by a unique code/binary value (1)
  • A standard set of characters so that text can be exchanged between computer systems (1)

Allow 'a list of characters that a computer can represent' for the first mark.

Do not accept a program/software that converts text into binary.

Do not accept 'a set of binary codes' on its own.

Example answers and how they were marked
Full marks2/2

A set of characters, such as letters, digits and punctuation, where each character is represented by a unique binary code.

Why: Set/collection of characters with examples (1) and each character has a unique code (1).

Some marks1/2

A set of letters and symbols that a computer can use to represent text.

Why: Awarded for the set/collection of characters (1); no creditworthy point saying each character has its own unique code (0).

No marks0/2

A program that converts the keys pressed on a keyboard into binary.

Why: Describes software that converts text, not a set of characters; the Do not accept line applies.

2Describe2 marksCharacter Sets Swap Remove

A computer uses 7-bit ASCII to store text.

Describe why 7 bits are needed to represent each character, rather than 6 bits.

[2 marks]
Mark scheme

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

  • 6 bits give only 64 different codes (1) which is fewer than the number of letters, digits and symbols that must be represented (1)
  • 7 bits give 128 different codes (1) which is enough to represent every letter, digit and symbol that is needed (1)
  • Adding a bit doubles the number of different codes from 64 to 128 (1) so that every character needed can have its own code (1)
  • There are more than 64 characters that must be represented (letters, digits and symbols) (1) so 6 bits cannot give each one a different code (1)

A statement of the number of codes without a development can earn one mark only; the development must be linked to the statement for the second mark.

Do not accept responses that only say computers use binary (1s and 0s).

Do not accept that 7 bits are needed because 7 is a bigger number than 6, with no reference to the number of codes or characters.

Do not accept responses about 8 bits, extended ASCII or Unicode.

Example answers and how they were marked
Full marks2/2

6 bits can only give 64 different codes, which is not enough for all the letters, digits and symbols that have to be represented.

Why: Gives the number of codes 6 bits can make (1) linked to the number of characters that must be represented (1).

Some marks1/2

7 bits give 128 different codes.

Why: States the number of codes available from 7 bits (1) but gives no linked development, so the second mark is not earned (0).

No marks0/2

Because computers only use binary and 7 is a bigger number than 6.

Why: Says only that computers use binary and compares the numbers, which the mark scheme tells markers not to accept; no creditworthy point about codes or characters.

3Explain2 marksCharacter Sets Swap Remove

A computer system uses a 4-bit code to represent the characters typed on its keyboard.

Explain one limitation of using 4 bits to represent characters.

[2 marks]
Mark scheme

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

  • Only 16 different characters can be represented (1) so there are not enough characters codes for every letter of the alphabet (1)
  • 4 bits give only 16 different combinations (1) which is not enough for the uppercase letters, lowercase letters, digits and symbols on a keyboard (1)
  • More than 16 characters are needed on a keyboard (1) so some letters, digits or symbols cannot be represented (1)
  • The number of character codes available is limited to 16 (1) because 4 bits give 2 to the power of 4 combinations (1)

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

Calculating that 4 bits give 2 to the power of 4 = 16 combinations can earn either the point or the linked reason, provided the other half of the answer says what this means (too few characters/codes).

Allow an expansion that names only the letters of the alphabet, e.g. there are not enough character codes for the 26 letters (1).

Do not accept '4 bits can only store 4 characters' (the number of bits is not the number of characters).

Do not accept 'it can only store 16 bits' (16 is the number of character codes/combinations, not the number of bits).

Do not accept 'not enough memory/storage' (the limitation is the number of character codes, not the amount of storage).

Do not accept 'it is limited/smaller' without saying how many characters/codes are available or what cannot be represented.

Example answers and how they were marked
Full marks2/2

Only 16 different characters can be represented, so there are not enough character codes for all 26 letters.

Why: Gives the point that only 16 characters can be represented (1) and links it to the reason that this is fewer than the letters needed (1).

Some marks1/2

Only 16 different characters can be represented.

Why: Gives the point that only 16 characters can be represented (1) but does not explain what cannot be represented.

No marks0/2

It can only store 4 characters because there are 4 bits.

Why: Misconception that the number of bits equals the number of characters, which the mark scheme says not to accept; no creditworthy point.

4Explain2 marksSound Swap Remove

Each sample of a sound wave is stored in binary using a fixed number of bits.

Explain one limitation of representing an analogue sound wave in binary when only a small number of bits is available for each sample.

[2 marks]
Mark scheme

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

  • Only a limited number of different amplitude values can be stored (1) so each sample is rounded to the nearest available value and the digital wave does not match the analogue wave exactly (1)
  • The wave is continuous but only a limited set of values can be represented (1) so amplitude detail/accuracy is lost (1)
  • Quiet and loud parts of the sound may be stored as the same value (1) because there are too few values to tell them apart (1)
  • The range of amplitudes that can be represented is limited (1) so the loudest/quietest parts of the sound cannot be stored accurately (1)

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

Do not award marks for answers that say the sound cannot be stored or heard at all.

Do not award answers about the number of samples taken/sample rate, as the number of bits limits the amplitude values, not how often the wave is sampled.

Do not accept 'lower quality'/'less accurate'/'less detail' on its own without a link to the amplitude values that can be stored/the number of bit combinations.

Do not accept 'the file size is smaller' without a link to the accuracy or the range of values that can be stored.

Example answers and how they were marked
Full marks2/2

Only a small number of amplitude values can be stored, so each sample is rounded to the nearest value and does not match the original wave exactly.

Why: Point (limited number of amplitude values) (1) with linked reason (samples are rounded and the wave is not exact) (1).

Some marks1/2

Only a small number of amplitude values can be stored.

Why: Creditworthy point (1) but no linked limitation such as rounding or lost accuracy, so only one mark.

No marks0/2

The sound cannot be stored at all because there are not enough bits to hold every sample.

Why: Misconception: the sound can still be stored, just less accurately, so no mark is awarded.

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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