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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 514 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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5 questions · 6 marks

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1Multiple 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.

2Multiple choice1 markUnits & Conversion Swap Remove

Units of data storage can be binary or decimal.

Identify the unit of storage that is equivalent to 1024 gibibytes.

[1 mark]
  • AGibibyte
  • BMebibyte
  • CTebibyte
  • DTerabyte
Mark scheme
  • C Tebibyte (1)
  • The only correct answer is C. The correct answer is tebibyte.
  • A is not correct because a gibibyte is 1024 mebibytes
  • B is not correct because a mebibyte is 1024 kibibytes
  • D is not correct because a terabyte is 1000 gigabytes
Example answers and how they were marked
Full marks1/1

C Tebibyte

Why: Correct: 1024 gibibytes make one tebibyte (1).

No marks0/1

A Gibibyte

Why: Near miss: a gibibyte is 1024 mebibytes, not 1024 gibibytes (0).

No marks0/1

D Terabyte

Why: Typical misconception: uses the decimal terabyte (1000 gigabytes) instead of the binary tebibyte (0).

3Multiple 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).

4Short recall1 markUnits & Conversion Swap Remove

A file has a size of 2 kibibytes.

State the number of bytes in the file.

[1 mark]
Mark scheme

Award one mark for:

  • 2048 (1)
  • 2 × 1024 (1)
  • 2^11 (1)

Allow 2048 bytes.

Do not accept 2000, which is the number of bytes in two decimal kilobytes.

Do not accept 1024, which is the number of bytes in one kibibyte.

Do not accept 16, which is the number of bits in two bytes.

Example answers and how they were marked
Full marks1/1

2048

Why: 2048 is 2 × 1024, the number of bytes in 2 kibibytes (1).

No marks0/1

2000

Why: 2000 uses the decimal kilobyte, not the binary kibibyte; the mark scheme does not accept it.

No marks0/1

16

Why: 16 is the number of bits in two bytes, confusing bits with bytes; the mark scheme does not accept it.

5Describe2 marksCompression Swap Remove

Data can be compressed using lossy or lossless compression.

Describe one difference between lossy compression and lossless compression.

[2 marks]
Mark scheme

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

  • Lossy compression permanently removes/discards some of the data (1) whereas lossless compression keeps all of the original data so the file can be restored/rebuilt exactly (1)
  • Lossy compression cannot reproduce/recreate the original file exactly (1) whereas lossless compression can decompress the file back to its original form (1)
  • Lossy compression can make a file smaller than lossless compression (1) because more of the original data is removed/discarded (1)
  • Lossy compression is used for images/sound/video (1) whereas lossless compression is used where all the original data must be kept, such as program files (1)

Allow one mark for a correct statement about one type of compression only, e.g. 'lossy compression permanently removes some data', with no comparison or development.

Do not accept 'lossy compression loses quality' on its own unless it states that data/information is removed or lost permanently.

Do not accept 'lossy is better' or 'lossless is safer' with no described difference.

Do not award a smaller file size on its own; it must be linked to data being removed or to no data being lost.

Example answers and how they were marked
Full marks2/2

Lossy compression permanently removes some of the data, whereas lossless compression keeps all of the original data so the file can be restored exactly.

Why: Linked difference: lossy permanently removes data (1) and lossless keeps all data so the file is restored exactly (1).

Some marks1/2

Lossy compression permanently removes some of the data.

Why: A correct statement about one type only (1), with no comparison to lossless or development, so the second mark is not earned.

No marks0/2

Lossless compression removes the data that is not needed so the file is smaller, but lossy compression keeps every bit of the data.

Why: The two types are the wrong way round; no creditworthy point, so no marks.

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