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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 · 5 marks

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1Multiple choice1 markCompression Swap Remove

A student downloads a compressed music file and then decompresses it.

Identify what is meant by decompression.

[1 mark]
  • AData is encrypted so that it cannot be read
  • BData is permanently removed to reduce the file size
  • CData is restored to its original format
  • DData is stored using fewer bits
Mark scheme
  • C Data is restored to its original format (1)
  • The only correct answer is C. The correct answer is data is restored to its original format.
  • A is not correct because encryption changes data so that it cannot be read without a key; it does not restore the data
  • B is not correct because permanently removing data to reduce the file size is lossy compression, not decompression
  • D is not correct because storing data using fewer bits is compression, not decompression
Example answers and how they were marked
Full marks1/1

C Data is restored to its original format

Why: Correct option (1).

No marks0/1

D Data is stored using fewer bits

Why: Near miss: this describes compression, not decompression.

No marks0/1

B Data is permanently removed to reduce the file size

Why: Misconception: this describes lossy compression, not decompression.

2Multiple choice1 markCompression Swap Remove

Identify one reason for using data compression.

[1 mark]
  • ATo increase the number of packets sent
  • BTo reduce the time taken to transmit a file
  • CTo improve the quality of the file
  • DTo make the file harder to open
Mark scheme
  • B To reduce the time taken to transmit a file (1)
  • The only correct answer is B. The correct answer is to reduce the time taken to transmit a file.
  • A is not correct because compression reduces file size, which can reduce the number of packets sent
  • C is not correct because lossy compression can reduce the quality of a file
  • D is not correct because encryption, not compression, can make a file harder to open
Example answers and how they were marked
Full marks1/1

B To reduce the time taken to transmit a file

Why: Correct option (1).

No marks0/1

A To increase the number of packets sent

Why: Near miss: compression reduces the number of packets sent, so no mark.

No marks0/1

C To improve the quality of the file

Why: Misconception that compression improves quality; no mark.

3Short recall1 markCompression Swap Remove

A company backs up its files to an external hard drive.

Give one reason why the company compresses the files before backing them up.

[1 mark]
Mark scheme

Award one mark for any of the following:

  • More files/data can be stored (in the same storage space) (1)
  • The files take up less storage space (1)
  • The backup is quicker/faster to complete (1)
  • Less data needs to be transferred to the backup device (1)

Do not accept 'makes the files more secure' or 'encrypts the files'.

Example answers and how they were marked
Full marks1/1

The compressed files take up less storage space, so more files can be backed up.

Why: The files take up less storage space (1).

No marks0/1

It reduces the amount of disk fragmentation.

Why: Near-miss: compression does not reduce disk fragmentation.

No marks0/1

It encrypts the files so they are safer if the drive is stolen.

Why: Misconception: compression does not encrypt files, and security is not accepted.

4Short recall2 marksUnits & Conversion Swap Remove

Data storage is measured in binary multiples.

Define the term bit.

[2 marks]
Mark scheme

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

  • A binary digit (1)
  • Has the value 0 or 1 (1)
  • The smallest unit of data storage (1)
  • A single 0 or 1 (1)

Allow binary digit/binary place value for binary digit

Allow a single binary digit for a single 0 or 1

Do not accept a group of 8 bits/half a nibble of 4 bits, which describe a byte or a nibble

Do not accept a binary number/binary on its own

Example answers and how they were marked
Full marks2/2

A binary digit that can have the value 0 or 1.

Why: A binary digit (1) and has the value 0 or 1 (1).

Some marks1/2

It is the smallest unit of data storage.

Why: Smallest unit of data storage (1), but does not state that it is a binary digit or that it has the value 0 or 1.

No marks0/2

A group of 8 bits.

Why: Describes a byte, not a bit; no creditworthy point and named in the Do not accept line.

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