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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

A text file stores each character using 7-bit ASCII.

Identify the denary ASCII code for the space character.

[1 mark]
  • A32
  • B33
  • C48
  • D65
Mark scheme
  • A 32 (1)
  • The only correct answer is A. The correct answer is 32.
  • B is not correct because 33 is the ASCII code for the exclamation mark (!)
  • C is not correct because 48 is the ASCII code for the character 0
  • D is not correct because 65 is the ASCII code for the uppercase letter A
Example answers and how they were marked
Full marks1/1

A 32

Why: Correct option: the space character has the ASCII code 32 (1).

No marks0/1

C 48

Why: Near miss scoring 0: 48 is the ASCII code for the character 0, not the space character.

No marks0/1

D 65

Why: Misconception scoring 0: 65 is the ASCII code for the uppercase letter A, so a well-known code is given but not the code for a space.

2Short recall2 marksSound Swap Remove

A sound wave is sampled and the amplitude of each sample is stored using a small number of bits.

Give two limitations of storing the sound in binary when only a small number of bits is available for each sample.

[2 marks]
Mark scheme

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

  • Only a limited/fixed number of amplitude values can be stored (1)
  • The amplitude of each sample is rounded/approximated to the nearest value that can be stored (1)
  • The recording is less accurate than the original analogue sound/does not match the analogue wave exactly (1)
  • Sounds louder than the highest amplitude that can be stored are clipped/distorted (1)
  • Sounds quieter than the lowest amplitude that can be stored cannot be represented/are lost (1)

Allow quantisation error/noise for the amplitude being rounded to the nearest value that can be stored, but do not award a second mark for the same idea

Allow a stated consequence as a separate mark only when it is a different point from the list, e.g. fewer amplitude values can be stored (1) so very quiet sounds are lost (1)

Do not accept 'lower quality'/'poorer sound' on its own; the answer must say the recording is less accurate than the original/does not match the analogue wave

Do not accept sample rate/sample interval/number of channels (stereo/mono), as these are not limited by the number of bits available for each sample

Do not accept remedies such as 'a larger bit depth would make it more accurate', as these do not describe a limitation

Do not accept answers about file size, compression or playback method

Do not accept a statement that repeats the stem, e.g. 'the sound is stored in binary using a fixed number of bits'

Example answers and how they were marked
Full marks2/2

The amplitude of each sample has to be rounded to the nearest value that can be stored, and very quiet sounds cannot be represented.

Why: Amplitude rounded to the nearest stored value (1) and quiet sounds cannot be represented (1): two different points from the list.

Some marks1/2

The recording is less accurate than the original sound.

Why: The recording is less accurate than the original analogue sound (1); a second, different limitation is not given.

No marks0/2

The sample rate is too low, so parts of the wave are missed.

Why: Sample rate is not limited by the number of bits per sample, so it is not accepted.

3Describe2 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.

4Explain2 marksCharacter Sets Swap Remove

The ASCII code for the uppercase letter A is 65, which is stored as the 7-bit pattern 1000001.

Explain why the lowercase letter a is stored using a different 7-bit pattern.

[2 marks]
Mark scheme

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

  • The computer needs to tell/distinguish the uppercase A from the lowercase a (1) because each different character has its own unique 7-bit code/pattern (1)
  • A and a are different characters (1) so each needs a different 7-bit pattern to be stored and displayed correctly (1)
  • If A and a had the same 7-bit pattern (1) the computer could not tell which character to display (1)

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

Do not accept 'because they are different letters/cases' without saying they need different/unique codes or that the computer must tell them apart.

Do not accept 'because A is a capital letter' on its own.

Do not accept 'because the codes are different numbers' or '65 is not 97' without linking to the need to tell the characters apart or to unique codes.

Example answers and how they were marked
Full marks2/2

Each character needs its own unique code, so the computer can tell that A and a are different characters and display the right one.

Why: Gives the point that the computer must tell A and a apart (1) and links it to the reason that each character needs its own unique code (1).

Some marks1/2

The computer must be able to tell the difference between uppercase and lowercase letters.

Why: Gives the point that the computer must tell the two characters apart (1) but gives no linked reason about unique codes or different 7-bit patterns.

No marks0/2

Because A is a capital letter and a is lowercase.

Why: Only states that the letters are different cases, which the mark scheme says is not accepted without saying they need unique codes or that the computer must tell them apart.

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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