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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 659 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 · 4 marks

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1Short recall2 marksCompression Swap Remove

Images and sound can be stored using lossy compression.

Define the term lossy compression.

[2 marks]
Mark scheme

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

  • Reduces the size of a file (1)
  • Permanently removes/loses some data (1)
  • The original file cannot be recreated/restored exactly (1)

Allow 'some data is deleted/discarded and cannot be recovered' for the second mark.

Do not award the first mark where the response also states that no data is lost.

Do not accept 'removes repeated data' (this describes lossless compression).

Example answers and how they were marked
Full marks2/2

Lossy compression reduces the size of a file by permanently removing some data, so the original cannot be restored exactly.

Why: Reduces the size of a file (1); permanently removes some data (1); maximum two marks awarded.

Some marks1/2

It makes a file smaller.

Why: Reduces the size of a file (1); no reference to data being permanently lost.

No marks0/2

It makes a file smaller without losing any of the data.

Why: States that no data is lost, which describes lossless compression; the first mark is not awarded.

2Explain2 marksUnits & Conversion Swap Remove

A server stores a large amount of data.

The capacity of the server is 16 TiB. Explain one benefit of giving the capacity in tebibytes rather than in bytes.

[2 marks]
Mark scheme

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

  • The capacity is easier to read/write (1) because a tebibyte is 1024^4 bytes so the same capacity in bytes would have many more digits (1)
  • The number is shorter (1) because writing 16 TiB instead of 17 592 186 044 416 bytes uses far fewer digits (1)
  • There is less chance of making a mistake when copying the value (1) because a long byte count of many digits is easy to mistype (1)

For both marks, the expansion must follow/associate with the statement and must refer to the number of digits/length of the value.

Allow 'fewer digits'/'shorter number'/'less chance of error' on its own for the first mark; the second mark needs the linked reason that a tebibyte is 1024^4 bytes, so the value in bytes would be very long/have many more digits.

Do not accept 'it is bigger'/'tebibytes are larger' on its own, as this does not give a benefit of using them.

Do not accept 'easier' on its own without saying what is easier, e.g. fewer digits/shorter number.

Do not accept 'because tebibytes are used for large storage' without a reason about the number of digits/readability.

Example answers and how they were marked
Full marks2/2

It is easier to read because 16 TiB has fewer digits than the same capacity written in bytes, which would be a very long number.

Why: Point that the number is easier to read (1); linked reason that the byte count would have many more digits (1).

Some marks1/2

It uses fewer digits.

Why: States the benefit of fewer digits (1); no linked reason about a tebibyte being 1024^4 bytes so the byte count is very long (0).

No marks0/2

Because a tebibyte is bigger than a byte.

Why: States a fact about the unit, which the mark scheme does not accept on its own; no point about fewer digits or readability, so no mark.

Questions by topic

5.3 Cybersecurity

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