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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 · 7 marks

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1Multiple choice1 markFetch Decode Execute Cycle Swap Remove

Identify the bus that carries memory addresses from the CPU to main memory. (1)

[1 mark]
  • AAddress bus
  • BControl bus
  • CData bus
  • DProgram counter
Mark scheme
  • A Address bus (1)
  • The only correct answer is A. The correct answer is address bus.
  • B is not correct because the control bus carries control signals
  • C is not correct because the data bus carries data and instructions
  • D is not correct because the program counter holds the address of the next instruction, it does not carry addresses
Example answers and how they were marked
Full marks1/1

A Address bus

Why: Correct option: the address bus carries memory addresses from the CPU to main memory (1).

No marks0/1

C Data bus

Why: Near-miss distractor: the data bus carries data and instructions between the CPU and main memory, not memory addresses (0).

No marks0/1

D Program counter

Why: Misconception: the program counter is a register that holds the address of the next instruction, it does not carry addresses to main memory (0).

2Short recall2 marksEmbedded Systems Swap Remove

An embedded system is a computer system built into another device to perform a specific function.

Give two examples of devices that contain an embedded system.

[2 marks]
Mark scheme

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

  • Microwave (oven) (1)
  • Washing machine (1)
  • Dishwasher (1)
  • Digital camera (1)
  • Satellite navigation/satnav system (1)
  • Traffic light(s) (1)
  • Central heating controller/thermostat (1)
  • Digital watch/fitness tracker (1)
  • Vending machine (1)
  • Car (as it contains embedded systems) (1)

Allow any other device that contains an embedded system.

Do not accept general purpose devices such as a laptop, desktop computer, tablet or smartphone (these can run many different programs).

Example answers and how they were marked
Full marks2/2

A microwave oven and a washing machine.

Why: Two creditworthy devices, a microwave oven (1) and a washing machine (1).

Some marks1/2

A dishwasher and a laptop computer.

Why: Dishwasher credited (1); laptop is a general purpose device, so not accepted.

No marks0/2

A desktop computer and a smartphone.

Why: Both are general purpose devices, so neither earns a mark.

3Describe2 marksStored Program Computers Swap Remove

A computer is based on the von Neumann stored program concept.

Describe how the CPU uses main memory (RAM) during the fetch-decode-execute cycle.

[2 marks]
Mark scheme

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

  • The program's instructions (and the data it uses) are held in main memory/RAM (1) so the CPU fetches both the instructions and the data from that one memory (1)
  • The CPU fetches the next instruction from main memory/RAM (1) using the address of the memory location that holds it (1)
  • The CPU reads/fetches data from main memory/RAM (1) when an instruction needs it and writes the result back to main memory/RAM (1)
  • The program's instructions are held in main memory/RAM while the program runs (1) and the CPU fetches them one at a time/one after another to be decoded and executed (1)

Allow 'memory' for main memory/RAM.

Allow 'gets' for fetches/reads.

For both marks, the development must say what the CPU does with the contents of main memory (fetches/reads/writes), not just that main memory is used.

Do not accept answers about the program being stored in secondary storage, such as on a hard drive, or about it being loaded from there.

Do not accept benefits such as the computer running faster or being easier for the user.

Do not accept naming CPU components (control unit, arithmetic logic unit, registers) or buses on their own, without saying what is stored or fetched.

Do not accept 'the computer stores data' on its own, without a link to the instructions of a program.

Example answers and how they were marked
Full marks2/2

The program's instructions and the data it uses are both held in the same main memory (RAM), so the CPU can fetch the instructions and the data it needs from that one memory.

Why: Linked point (1) that instructions and data are stored together in main memory, with the development (1) that the CPU fetches both from the same memory.

Some marks1/2

The CPU fetches the instructions from main memory so that they are processed more quickly.

Why: The first point earns (1) for the CPU fetching instructions from main memory. The second statement is a benefit (speed), which the 'Do not accept benefits' line rules out, so it earns nothing.

No marks0/2

The control unit decodes each instruction and the ALU carries out the calculations.

Why: Both statements name CPU components without saying what is stored, fetched or written, which the mark scheme tells examiners not to accept, so neither earns a mark.

4Explain2 marksFetch Decode Execute Cycle Swap Remove

The control unit is part of the CPU.

Explain the 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:

  • Decodes/interprets/translates the instruction (1) to work out what the instruction is/what operation is required (1)
  • Sends control signals to the other components (1) so that the correct component carries out the instruction (1), e.g. the ALU/main memory
  • Controls the fetch of the instruction from main memory (1) because the address of the next instruction is sent via the address bus (1)
  • Controls the fetch of the next instruction from main memory (1) by sending a control signal/read signal to main memory (1)

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

For the decode point, 'decodes the instruction' alone gains 1 mark; a second mark needs the purpose of decoding, i.e. working out what the instruction is/what operation is required.

Do not accept 'it controls the CPU' on its own, without naming a task in the cycle.

Do not accept 'it fetches the instruction from memory' on its own, as this describes the fetch step rather than the control unit's role; credit only if linked to controlling/signalling the fetch.

Do not accept carrying out arithmetic/logical operations, as these are carried out by the ALU, or holding the address of the next instruction, as this is the program counter.

Do not accept storing the instruction in a register (e.g. MAR/MDR), as this is not the role of the control unit.

Example answers and how they were marked
Full marks2/2

The control unit decodes each instruction, working out what it means, so that the CPU knows which component should carry it out.

Why: Linked point (1) and reason (1): decodes/interprets the instruction, and works out what it is/what operation is required.

Some marks1/2

It decodes the instruction that has been fetched from main memory.

Why: Decode point only (1); it does not explain the purpose of decoding, i.e. working out what the instruction is/what operation is required.

No marks0/2

It adds the two numbers together and stores the result in a register.

Why: Misconception: arithmetic is carried out by the ALU, which the mark scheme's Do not accept line covers.

Questions by topic

2.1 Binary

Build a paper on this topic 58
Adding Binary Numbers 6 questions Binary and Hexadecimal Basics 10 questions Binary Shifts 6 questions Binary to Denary Conversion 6 questions Binary to Hexadecimal Conversion 6 questions Denary to Binary Conversion 6 questions Denary to Hexadecimal Conversion 6 questions Denary to Negative Binary Conversion 6 questions Hexadecimal to Binary Conversion 6 questions

2.2 Data representation

Build a paper on this topic 56
Character Sets 18 questions Images 19 questions Sound 19 questions

2.3 Data storage and compression

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Compression 18 questions Units & Conversion 6 questions

3.1 Hardware

Build a paper on this topic 77
Embedded Systems 17 questions Fetch Decode Execute Cycle 15 questions Primary Memory 15 questions Secondary Memory 15 questions Stored Program Computers 15 questions

3.2 Software

Build a paper on this topic 124
File Management 18 questions Memory Management 16 questions Peripheral Management 11 questions Process Management 12 questions Purpose & Function of Operating Systems 17 questions Software Basics 13 questions User Management 18 questions Utility Software 19 questions

3.3 Programming languages

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Low and High Level Languages 19 questions Translators 18 questions

4.1 Networks

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Addressing 16 questions LANs & WANs 16 questions Network Speed 5 questions Packet Switching 16 questions Protocols & Layers 17 questions The Internet 16 questions Topologies 17 questions Wired Connections 17 questions Wireless Connections 18 questions

4.2 Network security

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Network Security Risks 18 questions Preventing Network Security Risks 18 questions

5.1 Environmental

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E-waste 17 questions Manufacturing Technology 19 questions

5.2 Ethical and legal

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Data Protection Act 17 questions Impact of AI 18 questions Intellectual Property 18 questions Software Licences 18 questions

5.3 Cybersecurity

Build a paper on this topic 36
Malware 18 questions Social Engineering 18 questions

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