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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 631 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 markUnits & Conversion Swap Remove

A computer stores data in binary.

Identify the number of bits in one kibibyte.

[1 mark]
  • A1024
  • B8000
  • C8192
  • D8 388 608
Mark scheme
  • C 8192 (1)
  • The only correct answer is C. The correct answer is 8192.
  • A is not correct because 1024 is the number of bytes in a kibibyte
  • B is not correct because 8000 is the number of bits in 1000 bytes
  • D is not correct because 8 388 608 is the number of bits in a mebibyte
Example answers and how they were marked
Full marks1/1

C 8192

Why: Correct: one kibibyte is 1024 bytes and 1024 × 8 = 8192 bits (1).

No marks0/1

A 1024

Why: Near miss: 1024 is the number of bytes in a kibibyte, not the number of bits (0).

No marks0/1

B 8000

Why: Typical misconception: uses 1000 bytes for a kibibyte, giving 1000 × 8 = 8000 bits (0).

2Describe2 marksCompression Swap Remove

A video streaming service stores many hours of video.

Describe one reason why the streaming service compresses its video files.

[2 marks]
Mark scheme

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

  • Makes each file smaller (1) so less secondary storage is needed for the videos (1)
  • Uses less bandwidth (1) so the video streams without buffering (1)
  • Reduces the amount of data sent (1) so users use less of their data allowance (1)
  • Can be streamed (1) because the data can be sent as fast as the user watches it (1)

Award one mark for a valid point on its own; the second mark is only awarded when the development is linked to that point.

Do not award a second mark for a development that repeats the point made.

Allow "takes less time to transmit/upload/download" as the development for a smaller file.

Do not accept responses that say compression saves memory/RAM (the videos are stored in secondary storage).

Do not accept compression makes the video more secure or improves its quality.

Example answers and how they were marked
Full marks2/2

It makes each video file smaller so the service needs less storage space for its library.

Why: Linked point: smaller file (1) and linked development: less storage needed (1).

Some marks1/2

It reduces the size of the video files.

Why: States that files are made smaller (1); no linked development is given, so the second mark is not awarded (0).

No marks0/2

It encrypts the video so it is safer to send.

Why: Gives security, which the mark scheme does not accept, not a reason for compression; no creditworthy point.

3Explain2 marksCompression Swap Remove

A solicitor sends large documents to clients by email.

Explain one reason why the solicitor compresses the documents before sending them.

[2 marks]
Mark scheme

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

  • The file size is reduced (1) so the documents take less time to transmit/send (1)
  • The compressed files are smaller (1) so they are more likely to be within the email attachment size limit (1)
  • Less data is sent (1) so less bandwidth/data allowance is used (1)
  • Fewer packets are needed (1) so the documents are received more quickly (1)

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

Do not accept 'it saves storage space' on its own without linking to sending the documents.

Do not accept 'it makes the file smaller' as both the point and the reason.

Example answers and how they were marked
Full marks2/2

The documents take up less space so they are quicker to send by email.

Why: File size reduced (1) and linked reason that transmission is quicker (1).

Some marks1/2

It makes the documents smaller.

Why: File size reduced (1) but no linked reason about sending or transmission.

No marks0/2

It reduces the amount of storage space the documents use on the client's computer.

Why: Storage space alone is not a reason for compressing before sending, so no linked explanation point is credited.

4Explain2 marksCompression Swap Remove

Files can be compressed using lossy or lossless compression.

Explain one difference between lossy compression and lossless compression.

[2 marks]
Mark scheme

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

  • Lossy compression permanently removes some data (1) whereas lossless compression does not remove any data (1)
  • With lossy compression the original file cannot be recreated exactly (1) but with lossless compression it can (1)
  • Lossy compression can produce a smaller file/a higher compression ratio (1) whereas lossless compression keeps all of the data so compresses less (1)

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

Allow 'removes data' for 'permanently removes data'.

A correct statement about only one type of compression, with no contrast, earns one mark.

Do not accept a reversed statement such as 'lossless compression loses data and lossy compression does not'.

Do not accept 'lossy makes the file smaller' on its own, because lossless compression also reduces the file size; the answer must say that data is removed.

Do not accept 'lossy is worse quality' on its own without saying data is removed.

Example answers and how they were marked
Full marks2/2

Lossy compression removes some data permanently, but lossless compression keeps all of the data.

Why: Lossy removes data permanently (1) and contrasts with lossless keeping all data (1).

Some marks1/2

Lossy compression removes some of the data.

Why: A correct statement about one type of compression with no contrast earns one mark (1); no contrasting statement about lossless compression is given.

No marks0/2

Lossless compression removes data so the file is smaller, but lossy compression keeps all the data.

Why: Reversed statement: lossless keeps all the data and lossy removes it, so no mark is awarded.

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