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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 604 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 · 6 marks

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1Multiple choice1 markCharacter Sets Swap Remove

A text file stores each character using 7-bit ASCII.

Identify the denary ASCII code for the space character.

[1 mark]
  • A32
  • B33
  • C48
  • D65
Mark scheme
  • A 32 (1)
  • The only correct answer is A. The correct answer is 32.
  • B is not correct because 33 is the ASCII code for the exclamation mark (!)
  • C is not correct because 48 is the ASCII code for the character 0
  • D is not correct because 65 is the ASCII code for the uppercase letter A
Example answers and how they were marked
Full marks1/1

A 32

Why: Correct option: the space character has the ASCII code 32 (1).

No marks0/1

C 48

Why: Near miss scoring 0: 48 is the ASCII code for the character 0, not the space character.

No marks0/1

D 65

Why: Misconception scoring 0: 65 is the ASCII code for the uppercase letter A, so a well-known code is given but not the code for a space.

2Short 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.

3Describe2 marksTranslators Swap Remove

A compiler and an interpreter both translate source code.

Describe one difference between what a compiler produces and what an interpreter produces.

[2 marks]
Mark scheme

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

  • A compiler produces object code/machine code/an executable (file) (1) whereas an interpreter produces no object code/translated file (1)
  • A compiler produces a machine code file (1) that can be run on its own/without the compiler/translator being present (1)
  • An interpreter produces no object code/file (1) because it translates and executes each line instead of saving translated code (1)
  • The compiler's output can be saved/stored (1) and run again later, while interpreted code has to be translated again each time it is run (1)

Allow binary for machine code.

Allow executable/an executable for object code.

Do not accept responses about translating the whole program, reporting errors or the speed of execution.

Do not accept 'the interpreter translates/executes one line at a time' on its own: this is how it translates, not what it produces. It earns the development only when linked to no object code/translated file being produced.

Do not accept the interpreter producing object code/an executable.

Example answers and how they were marked
Full marks2/2

A compiler produces object code, which is saved as a file, whereas an interpreter does not produce a file because it translates and executes each line.

Why: Compiler produces object code (1) contrasted with the interpreter producing no object code/translated file (1).

Some marks1/2

The compiler produces machine code.

Why: Machine code/object code produced (1); there is no contrast with the interpreter, so the development is not earned.

No marks0/2

The interpreter produces object code for each line it translates.

Why: Reverses the translators' outputs: the interpreter produces no object code, so nothing is creditworthy.

4Explain2 marksPacket Switching Swap Remove

A file is sent across the internet in packets.

Explain why packets from the same file may take different routes.

[2 marks]
Mark scheme

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

  • Each router chooses the best route at the time (1) so when a route becomes busy/congested or fails, later packets are forwarded along a different path (1)
  • Routers forward each packet separately (1) so the path a packet takes depends on the traffic conditions when that packet arrives (1)
  • A router may send a packet to a different next router (1) if its routing table shows a better/less congested route for that packet (1)
  • Traffic on the internet changes (1) so no single path is kept for the file and each packet can use whichever route is best when it is sent (1)

For both marks, the expansion must follow/associate with the statement.

Allow reference to a routing table, or to how a router decides the route, as part of the linked reason.

Do not accept 'the packets have different IP addresses' because all packets from the same file have the same destination IP address, even though their routes can differ.

Do not accept 'the internet is busy' or 'there is a lot of traffic' on its own without linking this to the router choosing a different route.

Do not accept 'different routers send the packets' on its own without a reason why a different router/route is chosen.

Do not accept an answer that only says the packets take different routes without explaining why.

Example answers and how they were marked
Full marks2/2

Each router chooses the best route at the time, so if one route becomes busy or fails, later packets are sent a different way.

Why: Linked point (1) that each router chooses the best route at the time and reason (1) that a busy or failed route means later packets take a different path.

Some marks1/2

Routers send packets along the least congested route.

Why: States that a router chooses the least congested route (1) but gives no linked reason why this makes the packets from the file take different routes.

No marks0/2

Because each packet is given a different IP address so they go to different places.

Why: Misconception named in the mark scheme: all packets from the same file share the same destination IP address, even though their routes can differ.

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