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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

Identify the definition of lossy compression.

[1 mark]
  • AData is removed only while the file is being transmitted
  • BData is permanently removed to reduce the file size
  • CData is restored exactly when it is decompressed
  • DData is stored using a dictionary of repeated patterns
Mark scheme
  • B Data is permanently removed to reduce the file size (1)
  • The only correct answer is B. The correct answer is data is permanently removed to reduce the file size.
  • A is not correct because the data removed by a lossy algorithm is not restored after transmission
  • C is not correct because that describes lossless compression, where the original file is rebuilt exactly
  • D is not correct because dictionary encoding is a lossless method that records repeated patterns once
Example answers and how they were marked
Full marks1/1

B Data is permanently removed to reduce the file size

Why: Correct option (1).

No marks0/1

C Data is restored exactly when it is decompressed

Why: Near miss: this describes lossless compression, so no mark.

No marks0/1

A Data is removed only while the file is being transmitted

Why: Misconception that compression only applies during transmission; the data is removed permanently, so no mark.

2Multiple 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).

3Multiple 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.

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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