Menu

Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 659 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.

Build a paper

Topics (none ticked: all of them)
Question types (none ticked: all of them)

Practice paper

3 questions · 6 marks

Pick again
Print
1Describe2 marksWireless Connections Swap Remove

A family uses a wireless network at home.

Describe how interference can affect the performance of a wireless network.

[2 marks]
Mark scheme

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

  • Other electrical/radio devices nearby (1) interfere with the wireless signal so data is corrupted (1)
  • Interference corrupts data (1) so the data has to be resent, which increases latency/slows the transfer (1)
  • Interference reduces the strength of the signal received (1) which lowers the data transfer rate the connection can support (1)
  • Interference makes the connection drop (1) so data transfer stops/devices have to reconnect (1)

Do not accept responses that only name a device (microwave, phone) without saying how it affects the network.

Do not accept responses that only state the network becomes slower without saying what causes the interference or how it affects the data.

Do not accept responses about wired connections or cables.

Example answers and how they were marked
Full marks2/2

Other electrical devices nearby can interfere with the wireless signal and corrupt data, so the data has to be resent and transfers are slower.

Why: Linked point: other electrical devices interfere and corrupt data (1), developed by the data being resent, which slows the transfer (1).

Some marks1/2

Other electrical devices nearby can interfere with the wireless signal.

Why: Cause given: other electrical devices interfere with the signal (1), but no development of how this affects the data or performance.

No marks0/2

Interference happens when the wireless cable is damaged by other cables.

Why: Misconception about cables; the mark scheme does not accept responses about wired connections or cables.

2Describe2 marksWired Connections Swap Remove

A hospital connects the computers on a ward using wired connections.

Describe how using wired connections can reduce latency on this network.

[2 marks]
Mark scheme

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

  • Data travels along the cable directly to the switch on a single continuous path (1) so the time between sending and receiving the data is short (1)
  • A cable is not affected by interference from other devices/wireless traffic nearby (1) so packets are not lost and resent, which would add to the delay (1)
  • The switch sends the data only to the port of the correct device, not to every device (1) so the data spends less time travelling and the delay is lower (1)
  • Fewer devices share a cable than share a wireless channel (1) so packets do not queue/wait before they are sent (1)

The first mark is for the way the wired connection carries the data; the second mark is for how this reduces the delay between sending and receiving.

Do not accept responses about bandwidth or the amount of data a cable can carry, as latency is the delay between sending and receiving.

Do not accept responses that confuse latency with speed/bandwidth, e.g. 'a wired connection is faster so there is less latency', unless they describe how the delay is reduced.

Do not accept answers that only say a wired connection is faster, with no link to the delay.

Example answers and how they were marked
Full marks2/2

The cable is not affected by interference from other devices so packets do not need to be resent and the delay stays low.

Why: First mark for the cable being free of interference (1); linked development that no packets are resent and so the delay is lower (1).

Some marks1/2

There is no interference from other devices on a cable.

Why: Gives the first point of a linked pair (1) but does not say how this reduces the delay between sending and receiving.

No marks0/2

Wired connections have a higher bandwidth so there is less latency.

Why: Confuses bandwidth with latency, which the 'Do not accept' lines rule out (0).

3Explain2 marksPacket Switching Swap Remove

Data is split into packets before it is sent across the internet.

Explain why each packet has a packet number in its header.

[2 marks]
Mark scheme

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

  • The receiver can put the packets back into the correct order (1) because packets may arrive out of order/take different routes (1)
  • The receiver can see if a packet is missing (1) because the sequence of numbers shows a gap (1)
  • The receiver knows when the whole file has arrived (1) because the total number of packets/last packet number is known (1)

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

Allow 'so the packets can be put back in the correct order/reassembled' for the first mark, but the second mark needs the reason, i.e. packets may arrive out of order/take different routes.

Do not accept 'so the packets can be identified' without stating what the number is used for, e.g. reordering or spotting a missing packet.

Do not accept 'so the router knows where to send it' - the router uses the destination IP address, not the packet number.

Example answers and how they were marked
Full marks2/2

The receiver can put the packets back in the correct order because they may arrive out of order.

Why: Linked point (1) and reason (1): the packet number allows reordering because packets can arrive out of order.

Some marks1/2

It shows the receiver the order of the packets.

Why: The point is given (1) but there is no linked reason, such as packets arriving out of order.

No marks0/2

So the router knows which route to use.

Why: Routers use the destination IP address, not the packet number, so this earns nothing; it is named in the mark scheme as a 'Do not accept'.

Questions by topic

5.3 Cybersecurity

More ways to revise Edexcel GCSE Computer Science (1CP2)

Teachers: build a paper, print it with the mark schemes at the end, and sign your school up to set your classes activities on every topic.

Fetch Decode Explain isn't affiliated with or endorsed by Pearson Edexcel.