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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 573 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 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.

2Describe2 marksLow and High Level Languages Swap Remove

A device driver is software that allows the operating system to control a piece of hardware. Device drivers are often written in a low-level programming language.

Describe one reason why a low-level programming language is suitable for writing a device driver.

[2 marks]
Mark scheme

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

  • Instructions can manipulate/control the hardware/memory/registers directly (1) so the driver can control the specific device it is written for (1)
  • The code is written for one specific processor/architecture (1) so it works with the exact hardware it will control (1)
  • The programmer controls exactly how memory/registers are used (1) so the code is efficient and needs little memory, which suits a device that has limited memory (1)
  • Each instruction maps to one machine code instruction (1) so the driver code is small enough to fit in the memory of the device (1)

Extra detail, such as naming the device the driver controls, is not needed to earn the marks.

Do not accept 'it is closer to machine code' on its own: it must be developed to show how this helps the driver, e.g. it can control the hardware directly.

Do not accept 'it is faster/quicker' with no link to the hardware/device, e.g. the device responds quickly.

Do not accept 'it is easier to learn', 'it is easier to debug' or 'it takes less time to write'.

Example answers and how they were marked
Full marks2/2

Low-level instructions can manipulate the hardware and memory directly (1) so the driver can control the specific device it was written for, such as a sound card (1).

Why: Point about direct control of hardware/memory (1) linked to controlling the specific device (1). The named device is extra detail and is not needed.

Some marks1/2

Low-level instructions can manipulate the hardware directly.

Why: Correct point (1) but no linked development saying how this helps the device driver.

No marks0/2

It is closer to machine code so it runs faster than a high-level language.

Why: 'Closer to machine code' is not developed into how this helps the driver, and 'runs faster' is not linked to the hardware/device, so no mark.

3Explain2 marksThe Internet Swap Remove

Every device that connects to the internet is given an IP address.

Explain one reason why every device on the internet needs a unique IP address.

[2 marks]
Mark scheme

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

  • Data/packets are delivered to the correct device (1) because the IP address identifies that device on the internet (1)
  • A reply is sent back to the device that made a request (1) because the sender's IP address is used as the destination address for the reply (1)
  • Routers can forward packets to the right device (1) because each packet's destination IP address matches only one device (1)
  • A device can be contacted by other devices (1) because other devices use its IP address to send data to it (1)

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

Allow 'so the router knows where to send data' only when expanded to say the IP address identifies the destination device / is used by routers to forward the packet to that device.

Do not accept 'so it can connect to the internet' / 'so it can access the internet' without saying how the address is used to identify the device or deliver data to it.

Do not accept 'so the device can be identified' on its own without saying what the identification is used for, e.g. delivering data or returning a reply.

Do not award a mark for restating that an IP address is unique / every device has a different address.

Example answers and how they were marked
Full marks2/2

So that data reaches the correct device. The IP address is how the internet tells one device apart from another, so packets are sent to that device and not to a different one.

Why: Point (1): data reaches the correct device. Reason (1): the IP address identifies/tells devices apart, so packets are sent to that device.

Some marks1/2

So that packets go to the right device, because every device has a different address.

Why: Point (1): packets go to the right device. The reason only restates that every device has a different address, which the mark scheme says does not earn the second mark.

No marks0/2

So it can connect to the internet.

Why: No linked explanation of how the address is used; 'so it can connect to the internet' is not accepted without expansion.

4Calculate2 marksAdding Binary Numbers Swap Remove

Computers manipulate binary patterns.

Complete the table to show the result of the 8-bit binary addition.

[2 marks]
1286432168421
10010101
01001111
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 1110 (1)
  • 0100 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

1110 0100

Why: 149 + 79 = 228, carrying where a column adds to 2: both nibbles are correct (2).

Some marks1/2

1110 0101

Why: A slip in the last bit. The first nibble is correct (1); the second is not.

No marks0/2

1101 1111

Why: Writes 1 in every column with a 1 and never carries. Neither nibble is correct.

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