Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• Bandwidth is the maximum amount/capacity of data that can be carried each second (1) so a higher bandwidth lets editors open the large video files from the server in less time (1)
• The bandwidth of the cable is set by the type/standard of cable used (1) so it limits how much of a large file can be sent in a given time (1)
• A higher bandwidth means the cable can be shared between more transfers at the same time (1) so several editors can open files from the server at once without their transfers slowing down (1)
• If the bandwidth is too low for the size of the files (1) the transfers take a long time and the editors have to wait for their files to open (1)

Allow 'capacity' for 'maximum amount of data'.

A description that only defines bandwidth earns a maximum of one mark.

Do not accept responses about the time a signal takes to travel (latency) or the distance a signal can reach (range).

Do not accept answers that say bandwidth is how fast the signal/data travels along the cable, that a higher bandwidth gives a faster internet connection, or that bandwidth is the number of cables in the network.

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.

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

• The speed of data transfer is reduced/is slower (1) because interference corrupts the radio signal, so data/packets are lost and have to be resent/retransmitted (1)
• The network speed is lower (1) because there is more noise on the wireless signal, so data is sent at a lower transmission rate (1)
• The throughput of the wireless network is reduced (1) because time is used resending corrupted data/packets instead of sending new data (1)

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

Award 1 mark for a statement that the speed/transfer rate is reduced (e.g. slower, takes longer), even if no reason is given.

Do not accept 'interference damages/corrupts the radio signal' or 'the signal is weaker' on its own without a link to the speed.

Do not accept 'data is lost' on its own without saying how this reduces the speed.

Do not accept 'interference increases the bandwidth' or 'interference makes the signal stronger'.