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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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3 questions · 5 marks

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1Multiple choice1 markCharacter Sets Swap Remove

Characters are encoded using 7-bit ASCII.

Identify the number of different characters that can be represented using 7-bit ASCII.

[1 mark]
  • A64
  • B127
  • C128
  • D256
Mark scheme
  • C 128 (1)
  • The only correct answer is C. The correct answer is 128.
  • A is not correct because 6 bits give only 64 different combinations
  • B is not correct because 127 is the largest 7-bit value, not the number of characters that 7 bits can represent
  • D is not correct because 256 characters need 8 bits, as used by 8-bit extended ASCII
Example answers and how they were marked
Full marks1/1

C 128

Why: Selects the only correct option (1): 7 bits give 2 to the power of 7, which is 128 different characters.

No marks0/1

D 256

Why: Near miss scoring 0: 256 is the number of characters that 8 bits give in extended ASCII, not 7-bit ASCII.

No marks0/1

B 127

Why: Misconception scoring 0, the off-by-one error the examiners' report describes: 127 is the largest 7-bit value, but 7 bits give 128 different characters.

2Short recall2 marksStored Program Computers Swap Remove

Computers use the von Neumann stored program concept.

Define the term stored program concept.

[2 marks]
Mark scheme

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

  • Program instructions are stored in main memory/RAM (1)
  • The data used by the program is stored in main memory/RAM (1)
  • The CPU fetches/reads instructions from main memory to execute them (1)
  • The program can be run without the instructions being input again (1)

Allow 'the program is stored in memory' for one mark.

Do not accept answers about programs being stored on secondary storage, such as a hard disk or USB memory stick.

Do not accept answers that only describe the von Neumann architecture (e.g. having a CPU and memory) without stating that instructions are stored in main memory.

Example answers and how they were marked
Full marks2/2

Both the program instructions and the data the program uses are held in the same main memory, and the CPU fetches these instructions from memory to execute them.

Why: Instructions stored in main memory (1) and the CPU fetches instructions from memory to execute them (1).

Some marks1/2

Program instructions are stored in main memory.

Why: Instructions stored in main memory (1). No second point about data being stored in the same memory or about the CPU fetching instructions.

No marks0/2

The program is saved on the hard disk so that it can be loaded into RAM when the user runs it.

Why: A near-miss about secondary storage, which the mark scheme says not to accept; the stored program concept is about instructions being held in main memory.

3Explain2 marksTopologies Swap Remove

A small office uses a star topology with a central switch.

Explain one benefit of using a star topology in the office.

[2 marks]
Mark scheme

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

  • If one cable/device fails, the other devices on the network are not affected (1) because each device has its own separate connection to the central switch (1)
  • Faults are easier to find (1) because each device has its own cable, so the faulty cable can be checked on its own (1)
  • Data is sent only to the intended device (1) because the central switch forwards the data only to the device it is addressed to (1)
  • Data transfer is fast (1) because each device has its own cable, so devices do not share the cable with each other (1)
  • New devices can be added easily (1) because a device only needs one cable to a spare port on the central switch (1)

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

A benefit stated on its own can earn one mark; the second mark is only for a linked reason.

Accept 'switch' for the central device.

Do not accept 'server' or 'hub' for the central device.

Do not accept 'hub', as a hub sends data to all devices, not only to the intended device.

Do not award a mark for responses that say only that the network is better/more reliable/easier without naming a benefit.

Example answers and how they were marked
Full marks2/2

If one of the cables breaks, the other devices can still communicate because each device has its own separate cable connected to the central switch.

Why: Linked benefit (1) and reason (1): a single cable failure does not affect the other devices because each device has a separate connection to the switch.

Some marks1/2

If one cable breaks, the other devices are not affected.

Why: A benefit is stated on its own (1), but there is no linked reason about each device having its own connection to the central switch, so the second mark is not awarded.

No marks0/2

It is better than a bus topology because every device connects to the central server.

Why: No credit: 'better' does not name a benefit, so no first mark, and 'server' is not accepted as the central device, so there is no linked reason either.

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