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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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3 questions · 5 marks

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1Multiple choice1 markStored Program Computers Swap Remove

Identify the component of the CPU that carries out arithmetic and logical operations.

[1 mark]
  • AArithmetic logic unit
  • BControl unit
  • CMain memory
  • DRegister
Mark scheme
  • A Arithmetic logic unit (1)
  • The only correct answer is A. The correct answer is arithmetic logic unit.
  • B is not correct because the control unit decodes instructions and controls the CPU
  • C is not correct because main memory is not part of the CPU and stores data and instructions
  • D is not correct because a register stores small amounts of data within the CPU
Example answers and how they were marked
Full marks1/1

A Arithmetic logic unit

Why: Correct option: the arithmetic logic unit carries out arithmetic and logical operations (1).

No marks0/1

B Control unit

Why: Control unit is a CPU component but its role is to decode and control, not perform arithmetic or logical operations, so no mark.

No marks0/1

D Register

Why: Register stores data but does not carry out operations; a common misconception that any CPU component performs calculations, so no mark.

2Short recall2 marksFetch Decode Execute Cycle Swap Remove

The control unit is one component of the CPU.

Give two roles of the control unit during the fetch-decode-execute cycle.

[2 marks]
Mark scheme

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

  • Decodes the instruction / works out what the instruction is (1)
  • Sends control signals to the other components (of the CPU) (1)
  • Coordinates/controls the activities of the CPU (1)
  • Directs the timing of the other components / controls when each component acts (1)

Do not accept carrying out arithmetic or logical operations, as this is the role of the ALU.

Do not accept holding/storing the data or instructions, as this is the role of the registers/main memory.

Example answers and how they were marked
Full marks2/2

It decodes each instruction and sends control signals to the other components to tell them what to do.

Why: Decodes the instruction (1) and sends control signals to the other components (1).

Some marks1/2

It decodes the instructions and carries out the calculations.

Why: Decoding the instruction (1); the calculations are carried out by the ALU, so the second part earns nothing.

No marks0/2

It stores the data that the CPU is working on.

Why: Storing data is the role of the registers/main memory, not the control unit, so no point is creditworthy.

3Describe2 marksSecondary Memory Swap Remove

A computer uses a magnetic hard disk.

Describe how data is stored on a magnetic hard disk.

[2 marks]
Mark scheme

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

  • A read/write head moves over the surface of the disk (1) to read/write data by detecting or changing the magnetic alignment of areas of the surface (1)
  • The head magnetises areas of the disk surface in different directions (1) so each area represents a binary 1 or 0 (1)
  • Data is stored on concentric circles called tracks (1) which are divided into sectors (1)

Allow one mark for tracks/concentric circles on their own.

For the second mark in the first two bullets, the response must refer to the magnetic alignment/charge being detected or changed, not just that the head reads/writes data.

Do not award a mark for 'it is magnetic' or 'it stores data in binary' with no description of how the data is stored.

Do not accept descriptions of optical storage (e.g. a laser, pits and lands) or solid state storage (e.g. electric charges in chips).

Example answers and how they were marked
Full marks2/2

The read/write head moves over the magnetic surface and magnetises areas of the disk to store the 1s and 0s.

Why: Head moves over the surface (1) and magnetises areas to represent 1s and 0s (1).

Some marks1/2

The data is stored on tracks on the disk.

Why: Tracks/concentric circles (1), but no development such as tracks divided into sectors.

No marks0/2

It is magnetic and saves the data in 1s and 0s.

Why: Near-miss: 'magnetic' alone and 'data in binary/1s and 0s' with no description of how data is stored, which the mark scheme does not award.

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