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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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2 questions · 3 marks

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1Multiple choice1 markCompression Swap Remove

Identify the statement that describes lossless compression.

[1 mark]
  • AData is encrypted so that it cannot be read by others
  • BData is permanently removed to make the file smaller
  • CNo data is lost and the original file can be recreated
  • DThe file is split into packets that are sent separately
Mark scheme
  • C No data is lost and the original file can be recreated (1)
  • The only correct answer is C. The correct answer is no data is lost and the original file can be recreated.
  • A is not correct because encryption hides data and does not make the file smaller
  • B is not correct because permanently removing data is lossy compression
  • D is not correct because splitting a file into packets is part of transmission, not compression
Example answers and how they were marked
Full marks1/1

C No data is lost and the original file can be recreated

Why: Correct option (1).

No marks0/1

B Data is permanently removed to make the file smaller

Why: Near miss: this is lossy compression, not lossless, so no mark.

No marks0/1

D The file is split into packets that are sent separately

Why: Misconception that compression is packet switching; no mark.

2Explain2 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.

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