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

5 questions · 8 marks

Pick again
Print
1Multiple choice1 markCharacter Sets Swap Remove

A text file stores each character using 7-bit ASCII.

Identify the denary ASCII code for the space character.

[1 mark]
  • A32
  • B33
  • C48
  • D65
Mark scheme
  • A 32 (1)
  • The only correct answer is A. The correct answer is 32.
  • B is not correct because 33 is the ASCII code for the exclamation mark (!)
  • C is not correct because 48 is the ASCII code for the character 0
  • D is not correct because 65 is the ASCII code for the uppercase letter A
Example answers and how they were marked
Full marks1/1

A 32

Why: Correct option: the space character has the ASCII code 32 (1).

No marks0/1

C 48

Why: Near miss scoring 0: 48 is the ASCII code for the character 0, not the space character.

No marks0/1

D 65

Why: Misconception scoring 0: 65 is the ASCII code for the uppercase letter A, so a well-known code is given but not the code for a space.

2Short recall1 markImages Swap Remove

A bitmap image uses one bit per pixel.

State the limitation this places on the number of colours in the image.

[1 mark]
Mark scheme

Award one mark for any of the following:

  • Only two different colours can be represented/stored (1)
  • Each pixel can only be one of two values (1)
  • The image can only be shown in black and white (1)

Allow answers that give the number of colours, e.g. two colours, 2 colours

Allow any pair of two colours, e.g. black and white, black and grey

Do not accept low resolution/poor quality/lower quality

Do not accept only one colour/can only show black

Do not accept 2 bits/2^1 without a statement about the number of colours that can be represented

Example answers and how they were marked
Full marks1/1

Only two colours can be represented, such as black and white.

Why: States that only two different colours can be represented (1)

No marks0/1

The image will have a low resolution.

Why: Confuses colour depth with resolution; low resolution is not accepted

No marks0/1

The image can only show black.

Why: One colour is all a single value can give; the limitation is that only two colours can be represented, so this is not accepted

3Explain2 marksCharacter Sets Swap Remove

A computer system uses a 4-bit code to represent the characters typed on its keyboard.

Explain one limitation of using 4 bits to represent characters.

[2 marks]
Mark scheme

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

  • Only 16 different characters can be represented (1) so there are not enough characters codes for every letter of the alphabet (1)
  • 4 bits give only 16 different combinations (1) which is not enough for the uppercase letters, lowercase letters, digits and symbols on a keyboard (1)
  • More than 16 characters are needed on a keyboard (1) so some letters, digits or symbols cannot be represented (1)
  • The number of character codes available is limited to 16 (1) because 4 bits give 2 to the power of 4 combinations (1)

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

Calculating that 4 bits give 2 to the power of 4 = 16 combinations can earn either the point or the linked reason, provided the other half of the answer says what this means (too few characters/codes).

Allow an expansion that names only the letters of the alphabet, e.g. there are not enough character codes for the 26 letters (1).

Do not accept '4 bits can only store 4 characters' (the number of bits is not the number of characters).

Do not accept 'it can only store 16 bits' (16 is the number of character codes/combinations, not the number of bits).

Do not accept 'not enough memory/storage' (the limitation is the number of character codes, not the amount of storage).

Do not accept 'it is limited/smaller' without saying how many characters/codes are available or what cannot be represented.

Example answers and how they were marked
Full marks2/2

Only 16 different characters can be represented, so there are not enough character codes for all 26 letters.

Why: Gives the point that only 16 characters can be represented (1) and links it to the reason that this is fewer than the letters needed (1).

Some marks1/2

Only 16 different characters can be represented.

Why: Gives the point that only 16 characters can be represented (1) but does not explain what cannot be represented.

No marks0/2

It can only store 4 characters because there are 4 bits.

Why: Misconception that the number of bits equals the number of characters, which the mark scheme says not to accept; no creditworthy point.

4Explain2 marksImages Swap Remove

Two versions of the same photograph are displayed at the same size on a screen. Version A is 800 × 600 pixels. Version B is 1600 × 1200 pixels.

Explain why Version B can show more detail.

[2 marks]
Mark scheme

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

  • Version B has more pixels in the same area (1) so each pixel represents a smaller part of the image (1)
  • Version B has a higher pixel density (1) so finer detail can be represented (1)
  • The pixels in Version B are smaller (1) so more detail can be captured in the same space (1)
  • Version B has a higher resolution (1) because there are more pixels per unit of area (1)

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

Do not accept 'more pixels' on its own without saying same area/pixel density/smaller pixels.

Do not accept higher colour depth or more colours.

Example answers and how they were marked
Full marks2/2

Version B has more pixels in the same area so each pixel represents a smaller part of the image.

Why: Linked point (1) and reason (1): more pixels in the same area means smaller pixels and more detail.

Some marks1/2

Version B has more pixels in the same area.

Why: One mark for the point about pixel density; the linked reason about smaller pixels or finer detail is missing.

No marks0/2

Version B has a higher colour depth, so it can display more colours.

Why: Colour depth is not the reason for more detail here; this is the common misconception that colour depth increases resolution.

5Explain2 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.

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.