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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 · 6 marks

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1Multiple choice1 markPrimary Memory Swap Remove

A computer is running an application. The application's data and instructions are transferred from secondary storage into RAM before the CPU processes them.

Identify the reason for this transfer.

[1 mark]
  • ARAM is non-volatile
  • BRAM is faster to access than secondary storage
  • CRAM has a larger capacity than secondary storage
  • DRAM is cheaper than secondary storage
Mark scheme
  • B RAM is faster to access than secondary storage (1)
  • The only correct answer is B. The correct answer is RAM is faster to access than secondary storage.
  • A is not correct because RAM is volatile
  • C is not correct because RAM has a smaller capacity than secondary storage
  • D is not correct because RAM is more expensive than secondary storage
Example answers and how they were marked
Full marks1/1

B RAM is faster to access than secondary storage

Why: Selects the correct option: RAM is faster to access than secondary storage, so data and instructions can reach the CPU quickly (1).

No marks0/1

A RAM is non-volatile

Why: Near miss: RAM is volatile; this does not explain the transfer into RAM.

No marks0/1

C RAM has a larger capacity than secondary storage

Why: Misconception: assumes primary memory has a larger capacity, but RAM has a smaller capacity than secondary storage.

2Multiple choice1 markStored Program Computers Swap Remove

Identify the bus that carries addresses in one direction only, from the CPU to main memory.

[1 mark]
  • AAddress bus
  • BControl bus
  • CData bus
  • DSystem bus
Mark scheme
  • A Address bus (1)
  • The only correct answer is A. The correct answer is address bus. Do not accept 'address' on its own.
  • B is not correct because the control bus carries control signals in both directions between the CPU and other components
  • C is not correct because the data bus carries data in both directions between the CPU and main memory
  • D is not correct because the system bus is the collection of all three buses
Example answers and how they were marked
Full marks1/1

A Address bus

Why: Correct option: the address bus carries addresses in one direction only, from the CPU to main memory (1).

No marks0/1

C Data bus

Why: The data bus carries data in both directions, so it is not the bus that carries addresses in one direction only from the CPU to main memory; no creditworthy point.

No marks0/1

B Control bus

Why: The control bus carries control signals in both directions, not addresses in one direction only; this is the common control/address bus confusion, so no mark.

3Explain2 marksEmbedded Systems Swap Remove

A greenhouse uses an embedded system to keep the plants healthy.

Explain how the embedded system controls the temperature in the greenhouse.

[2 marks]
Mark scheme

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

  • A temperature sensor measures/reads the temperature in the greenhouse (1) which the processor compares with the value stored in the system (1)
  • The heater is switched on (1) when the temperature reading goes below the value stored in the system (1)
  • A fan/vent/window is opened/a cooler is switched on (1) when the temperature reading goes above the value stored in the system (1)
  • The temperature is checked/measured continuously (1) so the heater/fan is switched on or off as soon as the temperature changes (1)

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

Allow one mark for a correct point on its own without a linked reason, e.g. 'a temperature sensor measures the temperature'.

Do not award 'the embedded system controls/keeps the temperature correct' as this repeats the question.

Do not accept naming a device without saying what it does, e.g. 'the greenhouse has a thermostat'.

Example answers and how they were marked
Full marks2/2

A temperature sensor measures the temperature in the greenhouse, which the processor compares with the value stored in the system.

Why: Point (1): the input and what it measures. Reason (1): the linked statement about what the processor does with the reading.

Some marks1/2

The embedded system uses a temperature sensor that measures the temperature in the greenhouse.

Why: A correct point on its own (1); no linked statement about what the system does with the reading, so the second mark is not awarded.

No marks0/2

The embedded system controls the temperature so the plants do not get too cold.

Why: Rewords the question without saying how the temperature is measured or changed, so no mark is awarded.

4Explain2 marksStored Program Computers Swap Remove

The control unit is a component of the CPU.

Explain one role of the control unit in the fetch-decode-execute cycle.

[2 marks]
Mark scheme

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

  • It decodes instructions (1) so the CPU knows what operation/instruction to perform (1)
  • It sends control signals (1) to coordinate/control the flow of data/instructions between components (1)
  • It manages/directs the fetch-decode-execute cycle (1) by controlling the sequence/timing of the stages (1)
  • It directs the other components of the CPU (1) so that each instruction is fetched/decoded/executed in the correct order (1)

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

Allow an explanation that the control unit directs data/instructions along the address/data/control buses (1) so the fetch-decode-execute cycle can take place (1)

Do not accept a generic 'it controls the CPU/components' point without linked expansion as to what is controlled/directed.

Do not accept 'it fetches instructions from memory' on its own; credit only if linked to the address/data/control buses or control signals.

Do not accept 'it stores/holds the instruction/data' as this is the role of a register.

Do not accept answers about the ALU performing calculations.

Example answers and how they were marked
Full marks2/2

It decodes instructions so the CPU knows which operation to carry out

Why: Linked point (1) and reason (1).

Some marks1/2

It decodes instructions.

Why: Creditworthy point (1) but no linked reason (0).

No marks0/2

It stores the instructions that are being executed.

Why: Misconception: storing/holding the instruction is the role of a register, not the control unit.

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