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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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1Multiple choice1 markCharacter Sets Swap Remove

Characters are encoded using 7-bit ASCII.

Identify the number of different characters that can be represented using 7-bit ASCII.

[1 mark]
  • A64
  • B127
  • C128
  • D256
Mark scheme
  • C 128 (1)
  • The only correct answer is C. The correct answer is 128.
  • A is not correct because 6 bits give only 64 different combinations
  • B is not correct because 127 is the largest 7-bit value, not the number of characters that 7 bits can represent
  • D is not correct because 256 characters need 8 bits, as used by 8-bit extended ASCII
Example answers and how they were marked
Full marks1/1

C 128

Why: Selects the only correct option (1): 7 bits give 2 to the power of 7, which is 128 different characters.

No marks0/1

D 256

Why: Near miss scoring 0: 256 is the number of characters that 8 bits give in extended ASCII, not 7-bit ASCII.

No marks0/1

B 127

Why: Misconception scoring 0, the off-by-one error the examiners' report describes: 127 is the largest 7-bit value, but 7 bits give 128 different characters.

2Short 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.

3Describe2 marksCharacter Sets Swap Remove

A computer uses 7-bit ASCII to represent characters.

The character M has the ASCII code 77. Describe how the character M is represented in the computer.

[2 marks]
Mark scheme

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

  • The denary code 77 is converted to binary (1) to give the 7-bit pattern 1001101 (1)
  • The character M is represented by a unique ASCII code/number (1) that is stored as a 7-bit binary pattern (1)
  • 7 bits are used to store the code for M (1) so 128 different characters can be represented (1)
  • The binary pattern 1001101 is stored in memory (1) using one 7-bit code for each character (1)

Do not accept answers that only state the ASCII code 77, as this is given in the question.

Do not accept 01001101, as this is an 8-bit pattern.

Do not accept ASCII described as a programming language or a method of encryption.

Example answers and how they were marked
Full marks2/2

77 is converted to binary, giving 1001101. This is stored using 7 bits for the character M.

Why: Linked description: converts the code to binary (1) to give the 7-bit pattern 1001101 (1).

Some marks1/2

77 is changed into binary so it can be stored.

Why: Gives the conversion of 77 to binary (1) but does not give the 7-bit pattern 1001101 (0).

No marks0/2

ASCII is a programming language that stores letters as numbers.

Why: Describes ASCII as a programming language, which the mark scheme says is not creditworthy; no linked description of how M is represented.

4Explain2 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.

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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