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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.

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5 questions · 9 marks

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1Short recall1 markAddressing Swap Remove

Routers forward data packets across the internet.

State the part of a data packet that a router uses to decide where to send it.

[1 mark]
Mark scheme

Award one mark for:

  • (Destination) IP address (1)

Allow IP address on its own (the destination is implied).

Do not accept source IP address/IP address of the sender.

Do not accept MAC address.

Do not accept domain name/web address.

Example answers and how they were marked
Full marks1/1

The destination IP address.

Why: Names the destination IP address (1).

No marks0/1

The domain name.

Why: A domain name is not used by a router to route a packet; it must be translated to an IP address first, so no mark.

No marks0/1

The MAC address.

Why: A MAC address is not used to route packets across the internet; the Do not accept line applies.

2Describe2 marksWired Connections Swap Remove

A farm uses wired connections to link sensors in its fields to a computer in the farmhouse.

Describe how the range of a wired connection can affect the performance of this network.

[2 marks]
Mark scheme

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

  • (Twisted pair/copper) cable only carries data over a limited distance (about 100 metres) (1) so sensors further away need another switch/device to pass the data on to the farmhouse (1)
  • Fibre optic cable can carry data over much longer distances (1) so wired connections can reach sensors across the whole farm (1)
  • Data sent further than the cable's range is not received (1) so the computer in the farmhouse does not get readings from those sensors (1)
  • A wireless connection can reach sensors that are out of range of the cables (1) so a mix of the two can give readings across the whole site (1)

Allow responses about signal weakening/being lost over a long cable.

Do not accept responses about bandwidth or speed, as range is about distance, not the amount or rate of data.

Example answers and how they were marked
Full marks2/2

Twisted pair copper cable only carries data for about 100 metres so a switch is needed in each field to pass the readings on to the farmhouse.

Why: Point that copper cable has a limited distance (1) linked to needing another device to extend the network (1).

Some marks1/2

Fibre optic cable can carry data much further than copper cable.

Why: Gives the first point of a linked pair (1) but does not develop it to say what this allows the farm to do.

No marks0/2

A longer cable gives the network a bigger bandwidth so the sensors work faster.

Why: About bandwidth and speed rather than range, which the mark scheme says is not accepted.

3Explain2 marksPacket Switching Swap Remove

A file is sent across the internet in packets.

Explain why packets from the same file may take different routes.

[2 marks]
Mark scheme

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

  • Each router chooses the best route at the time (1) so when a route becomes busy/congested or fails, later packets are forwarded along a different path (1)
  • Routers forward each packet separately (1) so the path a packet takes depends on the traffic conditions when that packet arrives (1)
  • A router may send a packet to a different next router (1) if its routing table shows a better/less congested route for that packet (1)
  • Traffic on the internet changes (1) so no single path is kept for the file and each packet can use whichever route is best when it is sent (1)

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

Allow reference to a routing table, or to how a router decides the route, as part of the linked reason.

Do not accept 'the packets have different IP addresses' because all packets from the same file have the same destination IP address, even though their routes can differ.

Do not accept 'the internet is busy' or 'there is a lot of traffic' on its own without linking this to the router choosing a different route.

Do not accept 'different routers send the packets' on its own without a reason why a different router/route is chosen.

Do not accept an answer that only says the packets take different routes without explaining why.

Example answers and how they were marked
Full marks2/2

Each router chooses the best route at the time, so if one route becomes busy or fails, later packets are sent a different way.

Why: Linked point (1) that each router chooses the best route at the time and reason (1) that a busy or failed route means later packets take a different path.

Some marks1/2

Routers send packets along the least congested route.

Why: States that a router chooses the least congested route (1) but gives no linked reason why this makes the packets from the file take different routes.

No marks0/2

Because each packet is given a different IP address so they go to different places.

Why: Misconception named in the mark scheme: all packets from the same file share the same destination IP address, even though their routes can differ.

4Explain2 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.

5Explain2 marksWireless Connections Swap Remove

A student plays an online game using a laptop connected to the school Wi-Fi.

Explain one reason why an online game can respond more slowly over a wireless connection than over a wired connection.

[2 marks]
Mark scheme

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

  • Wireless signals can be blocked or absorbed by walls (1) so the data must be re-sent, which adds delay (1)
  • A device further from the access point has a weaker signal (1) so data must be re-sent/transmitted at a lower rate, adding delay (1)
  • Devices on a wireless network share a channel (1) so a device must wait its turn to transmit, which adds delay (1)
  • Interference from other devices affects the radio signal (1) so data must be re-sent, adding delay (1)

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

Allow 'waiting to send' or 'collisions' as the delay caused by devices sharing a channel.

Do not accept 'wireless is slower than wired' on its own, as this repeats the question.

Do not accept a reason that only affects download speed/bandwidth (e.g. 'files take longer to download') without a link to delay.

Example answers and how they were marked
Full marks2/2

Interference from other devices affects the radio signal, so the data has to be re-sent and this adds delay before the player's action appears.

Why: Linked point (1): interference affects the signal; reason (1): re-sending the data adds delay (latency).

Some marks1/2

Walls can block the wireless signal.

Why: Point only (1): walls block the signal. No linked reason saying that this means data must be re-sent, which adds delay.

No marks0/2

Wireless has less bandwidth than wired, so a game update takes longer to download.

Why: Confuses latency with bandwidth/download speed; the mark scheme says not to accept this without a link to delay.

Questions by topic

5.3 Cybersecurity

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