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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

RAM is the main memory of a computer.

Identify the effect on the contents of RAM when the computer is switched off.

[1 mark]
  • AThey are lost
  • BThey are stored permanently
  • CThey are saved to secondary storage
  • DThey are written to ROM
Mark scheme
  • A They are lost (1)
  • The only correct answer is A. The correct answer is They are lost
  • B is not correct because RAM is volatile and its contents are lost when the power is switched off, so they are not stored permanently
  • C is not correct because RAM is volatile and its contents are lost when the power is switched off, so they are not saved to secondary storage
  • D is not correct because ROM is read-only memory that holds the start-up instructions, so the contents of RAM are not written to it
Example answers and how they were marked
Full marks1/1

A They are lost

Why: Selected the correct option. RAM is volatile, so its contents are lost when the power is switched off (1).

No marks0/1

C They are saved to secondary storage

Why: Near miss: thinks RAM contents are automatically saved, but RAM is volatile and its contents are not saved to secondary storage (0).

No marks0/1

B They are stored permanently

Why: Misconception: thinks RAM is non-volatile and keeps data permanently, but RAM is volatile and loses its contents when the power is switched off (0).

2Multiple choice1 markStored Program Computers Swap Remove

Identify the function of the control unit in the fetch-decode-execute cycle.

[1 mark]
  • ADecodes instructions
  • BPerforms arithmetic operations
  • CStores data and instructions
  • DTemporarily stores data being processed
Mark scheme
  • A Decodes instructions (1)
  • The only correct answer is A. The correct answer is Decodes instructions.
  • B is not correct because the arithmetic logic unit performs arithmetic operations
  • C is not correct because main memory stores data and instructions
  • D is not correct because registers temporarily store data being processed
Example answers and how they were marked
Full marks1/1

A Decodes instructions

Why: Correct option: the control unit decodes instructions during the fetch-decode-execute cycle (1).

No marks0/1

C Stores data and instructions

Why: Main memory stores data and instructions, not the control unit; this is a common distractor, so no mark.

No marks0/1

B Performs arithmetic operations

Why: Arithmetic operations are performed by the ALU, not the control unit; a common confusion between CPU components, so no mark.

3Short recall2 marksStored Program Computers Swap Remove

The central processing unit (CPU) contains an arithmetic logic unit (ALU).

State two types of operation carried out by the ALU.

[2 marks]
Mark scheme

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

  • An arithmetic operation, e.g. addition/subtraction/multiplication/division (1)
  • A logical operation, e.g. comparing two values (is A > B?) / using AND, OR, NOT (1)

Do not accept decoding instructions, fetching instructions or controlling the timing of the CPU, as these are carried out by the control unit.

Example answers and how they were marked
Full marks2/2

It carries out arithmetic operations such as addition and subtraction, and logical operations such as comparing two values to see if one is greater than the other.

Why: Arithmetic operation (1) and logical operation (1).

Some marks1/2

It adds numbers together and works out the result.

Why: Arithmetic operation, addition (1). No logical operation.

No marks0/2

It decodes the instructions that have been fetched from main memory.

Why: Decoding and fetching are the control unit's role; the mark scheme's do-not-accept line covers this.

4Explain2 marksSecondary Memory Swap Remove

A hard disk drive stores data on a spinning magnetic platter.

Explain how data is read from a magnetic hard disk.

[2 marks]
Mark scheme

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

  • The read/write head moves over the surface of the platter (1) and detects whether each area of the disk is magnetised (1)
  • The platter spins/rotates (1) so the read/write head can pass over the whole surface/tracks of the disk (1)
  • The pattern of magnetised and non-magnetised areas detected by the read/write head (1) is read as binary 1s and 0s (1)
  • The drive head detects the direction of magnetisation of each area (1) so the data can be read as binary (1)

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

Allow one mark for stating that data is read magnetically / that the read/write head detects the magnetisation of the disk without a linked reason.

Do not accept answers that describe how data is written to the disk, such as the head magnetising the platter, rather than how it is read.

Do not accept 'a laser reads the pits and lands' - this describes optical storage, not magnetic storage.

Example answers and how they were marked
Full marks2/2

The platter rotates so the read/write head passes over the whole surface of the disk and it detects whether each area is magnetised or not. The pattern of magnetised areas is then read as 1s and 0s.

Why: Linked point (1) rotation of the platter with reason (1) the head reaches the whole surface, and the second line about magnetised areas is also present.

Some marks1/2

The read/write head detects the magnetic charges on the disk.

Why: Allow line (1): states the head detects the magnetisation of the disk, but gives no linked reason (e.g. the platter rotating so the head covers the whole surface), so only one mark.

No marks0/2

A laser shines onto the disk and reads the pits and lands, then the data is sent to the CPU.

Why: Describes optical storage. Do not accept 'a laser reads the pits and lands' - a magnetic disk is read by a head detecting magnetisation.

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