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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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4 questions · 6 marks

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1Multiple choice1 markImages Swap Remove

Identify the smallest identifiable area of a bitmap image.

[1 mark]
  • AColour depth
  • BFile size
  • CPixel
  • DResolution
Mark scheme
  • C Pixel (1)
  • The only correct answer is C. The correct answer is pixel.
  • A is not correct because colour depth is the number of bits used to store the colour of each pixel
  • B is not correct because file size is the amount of storage an image takes up, not an area of the image
  • D is not correct because resolution is a measure of the number of pixels in an image (such as its width × height), not the smallest identifiable area
Example answers and how they were marked
Full marks1/1

C Pixel

Why: Correct option; a pixel is the smallest identifiable area of a bitmap image (1).

No marks0/1

D Resolution

Why: Resolution is a measure of the number of pixels in an image, not the smallest identifiable area; no mark.

No marks0/1

A Colour depth

Why: Colour depth is the number of bits used to store each pixel's colour, not the smallest identifiable area; no mark.

2Short recall1 markCharacter Sets Swap Remove

A computer can store a maximum of 80 bits for a text message. Each character is stored using 7-bit ASCII.

State the maximum number of whole characters that can be stored in the message.

[1 mark]
Mark scheme

Award one mark for:

  • 11 (characters) (1)

Allow 11 remainder 3.

Allow 80 ÷ 7 = 11.428... rounded down to 11.

Do not accept 11.4 or 12 (rounding up or giving a decimal answer).

Do not award an unevaluated calculation such as 80 ÷ 7 with no answer.

Example answers and how they were marked
Full marks1/1

11

Why: Correct: 80 ÷ 7 = 11 remainder 3, so 11 whole characters can be stored (1).

No marks0/1

11.4

Why: Near miss: gives a decimal result rather than the number of whole characters; the mark scheme does not accept 11.4.

No marks0/1

12

Why: Rounds up to 12, but 12 characters would need 84 bits, more than the 80 available; the mark scheme does not accept 12.

3Describe2 marksCharacter Sets Swap Remove

A computer uses 7-bit ASCII to store text.

Describe why 7 bits are needed to represent each character, rather than 6 bits.

[2 marks]
Mark scheme

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

  • 6 bits give only 64 different codes (1) which is fewer than the number of letters, digits and symbols that must be represented (1)
  • 7 bits give 128 different codes (1) which is enough to represent every letter, digit and symbol that is needed (1)
  • Adding a bit doubles the number of different codes from 64 to 128 (1) so that every character needed can have its own code (1)
  • There are more than 64 characters that must be represented (letters, digits and symbols) (1) so 6 bits cannot give each one a different code (1)

A statement of the number of codes without a development can earn one mark only; the development must be linked to the statement for the second mark.

Do not accept responses that only say computers use binary (1s and 0s).

Do not accept that 7 bits are needed because 7 is a bigger number than 6, with no reference to the number of codes or characters.

Do not accept responses about 8 bits, extended ASCII or Unicode.

Example answers and how they were marked
Full marks2/2

6 bits can only give 64 different codes, which is not enough for all the letters, digits and symbols that have to be represented.

Why: Gives the number of codes 6 bits can make (1) linked to the number of characters that must be represented (1).

Some marks1/2

7 bits give 128 different codes.

Why: States the number of codes available from 7 bits (1) but gives no linked development, so the second mark is not earned (0).

No marks0/2

Because computers only use binary and 7 is a bigger number than 6.

Why: Says only that computers use binary and compares the numbers, which the mark scheme tells markers not to accept; no creditworthy point about codes or characters.

4Explain2 marksSound Swap Remove

Analogue sound is converted to binary by sampling at regular intervals.

Explain one reason why increasing the sample rate improves the quality of a digitised sound.

[2 marks]
Mark scheme

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

  • More samples are taken every second / the sample rate is higher (1) so the digital wave follows the shape of the analogue wave more closely (1)
  • The amplitude is measured more often / at shorter intervals (1) so fewer changes in the sound are missed between measurements (1)
  • The sample interval is shorter (1) so less of the sound wave is lost/goes unrecorded between samples (1)
  • More data points are recorded for the same length of sound (1) so the digital representation is a closer copy of the original sound (1)

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

Do not accept 'the quality is better/higher' or 'the sound is clearer' as a point on its own without a reason such as more samples or more detail.

Do not accept 'the samples are more accurate' or 'more data is collected' without saying what becomes more accurate or what the extra data records.

Do not accept 'the file size is larger' as a reason for improved quality.

Do not accept answers about using more bits per sample, as these describe bit depth, not the sample rate.

Example answers and how they were marked
Full marks2/2

More samples are taken every second, so the digital representation follows the shape of the analogue wave more closely.

Why: Point (more samples each second) (1) with linked reason (follows the analogue wave more closely) (1).

Some marks1/2

More samples are taken every second.

Why: Creditworthy point (1) but no linked reason about what the extra samples achieve, so stays on one mark.

No marks0/2

Each sample is stored using more bits, so every measurement is more accurate.

Why: This describes bit depth, not the sample rate, so neither mark is awarded.

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