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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 markAddressing Swap Remove

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

Identify the number of bits in an IPv4 address.

[1 mark]
  • A4
  • B8
  • C32
  • D128
Mark scheme
  • C 32 (1)
  • The only correct answer is C. The correct answer is 32.
  • A is not correct because 4 is the number of groups of numbers in an IPv4 address
  • B is not correct because 8 is the number of bits in each group of an IPv4 address
  • D is not correct because 128 is the number of bits in an IPv6 address
Example answers and how they were marked
Full marks1/1

C 32

Why: Correct option (1): an IPv4 address is 32 bits long.

No marks0/1

B 8

Why: 8 is the number of bits in one group of an IPv4 address, not the whole address (mark scheme line B), so no mark.

No marks0/1

D 128

Why: 128 is the length of an IPv6 address, not an IPv4 address (mark scheme line D), so no mark.

2Explain2 marksPacket Switching Swap Remove

A router connects a home network to the internet.

Explain how a router uses the destination IP address in a packet header.

[2 marks]
Mark scheme

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

  • The router reads the destination IP address (1) so it knows which network/device the packet is for (1)
  • The router looks up the destination IP address in its routing table (1) to find the next router/route for the packet (1)
  • The router forwards the packet to the next router (1) that leads towards that IP address / is on the best route (1)

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

Do not accept MAC address - routers use the IP address to route packets between networks.

Do not accept 'it finds the exact device' without saying how the router uses the address, e.g. routing table/next router.

Example answers and how they were marked
Full marks2/2

The router looks up the destination IP address in its routing table to find the next router to send the packet to.

Why: Linked point (1) and reason (1): looks up the destination IP address in the routing table to find the next router.

Some marks1/2

It reads the destination IP address.

Why: Reads the destination IP address (1) but gives no linked reason about a routing table or next router.

No marks0/2

It reads the MAC address so it knows which computer sent the packet.

Why: Routers use the IP address to route packets, not the MAC address; no creditworthy point.

3Explain2 marksTopologies Swap Remove

A bus topology has a terminator at each end of its cable.

Explain why terminators are needed in a bus topology.

[2 marks]
Mark scheme

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

  • Terminators absorb the signal at the ends of the cable (1) so it is not reflected back along the bus (1)
  • Terminators prevent signals reflecting/bouncing back (1) so the reflected signal does not corrupt data on the cable (1)
  • Terminators absorb the signal (1) so it does not collide/interfere with data being sent by other devices (1)
  • Terminators stop the signal reflecting back down the cable (1) so data can be transmitted and received without errors (1)

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

Allow 'interfere'/'corrupt' only where the answer says the reflected signal mixes with/collides with data on the cable.

Do not accept 'to stop the signal' on its own, as stopping the signal is not the same as stopping it reflecting back along the cable.

Do not accept 'to terminate the cable/network', 'to end the cable' or 'to stop the cable breaking'.

Do not award responses that only repeat the stem, e.g. 'because there is a terminator at each end'.

Example answers and how they were marked
Full marks2/2

Terminators absorb the signal at each end of the cable so that it does not reflect back along the bus.

Why: Linked point (1) and reason (1): absorbing the signal is linked to it not being reflected back along the bus.

Some marks1/2

Terminators absorb the signal at the ends of the cable.

Why: Awarded 1 mark for the point that the signal is absorbed, but no linked consequence is given.

No marks0/2

They terminate the network so the cable does not break.

Why: No credit: it does not say the signal is absorbed or that reflections are prevented, and the mark scheme rejects 'to terminate the network' and 'to stop the cable breaking'.

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