Edexcel GCSE Computer Science (1CP2) Exam Questions

Award one mark for:

• 2048 (1)
• 2 × 1024 (1)
• 2^11 (1)

Allow 2048 bytes.

Do not accept 2000, which is the number of bytes in two decimal kilobytes.

Do not accept 1024, which is the number of bytes in one kibibyte.

Do not accept 16, which is the number of bits in two bytes.

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

• Some data is removed permanently (1) choosing detail that people are least likely to notice (1)
• Small changes in colour/shade are discarded (1) so fewer different values need to be stored (1)
• Similar pixels are stored as one value (1) so there are fewer values in the file (1)
• Fine detail is removed (1) so fewer bits are needed to store each area (1)

Do not accept answers that say repeated patterns are stored once / no data is lost.

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

• The file size is reduced (1) so the documents take less time to transmit/send (1)
• The compressed files are smaller (1) so they are more likely to be within the email attachment size limit (1)
• Less data is sent (1) so less bandwidth/data allowance is used (1)
• Fewer packets are needed (1) so the documents are received more quickly (1)

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

Do not accept 'it saves storage space' on its own without linking to sending the documents.

Do not accept 'it makes the file smaller' as both the point and the reason.