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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 604 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 markCharacter Sets Swap Remove

Characters are encoded using 7-bit ASCII.

Identify the number of different characters that can be represented using 7-bit ASCII.

[1 mark]
  • A64
  • B127
  • C128
  • D256
Mark scheme
  • C 128 (1)
  • The only correct answer is C. The correct answer is 128.
  • A is not correct because 6 bits give only 64 different combinations
  • B is not correct because 127 is the largest 7-bit value, not the number of characters that 7 bits can represent
  • D is not correct because 256 characters need 8 bits, as used by 8-bit extended ASCII
Example answers and how they were marked
Full marks1/1

C 128

Why: Selects the only correct option (1): 7 bits give 2 to the power of 7, which is 128 different characters.

No marks0/1

D 256

Why: Near miss scoring 0: 256 is the number of characters that 8 bits give in extended ASCII, not 7-bit ASCII.

No marks0/1

B 127

Why: Misconception scoring 0, the off-by-one error the examiners' report describes: 127 is the largest 7-bit value, but 7 bits give 128 different characters.

2Short recall2 marksEmbedded Systems Swap Remove

A digital camera contains an embedded system.

Give two functions that the embedded system performs in the digital camera.

[2 marks]
Mark scheme

Award one mark for any of the following up to a maximum of two marks:

  • Focus the lens/autofocus (1)
  • Control the shutter (speed) (1)
  • Control the flash/decide when the flash is needed (1)
  • Measure the light level to set the exposure/the aperture (1)
  • Stabilise the lens/image stabilisation (1)
  • Zoom the lens in and out (1)
  • Detect a face/smile (1)

Do not accept 'take a photograph'/'take a picture'/'capture an image', as taking photographs is the function of the camera, which is given in the question.

Do not accept 'press the button' as this is an action of the user, not a function performed by the embedded system.

Do not accept vague answers such as 'use the camera', 'turn the camera on and off' or 'make the camera work', which do not name a function that the embedded system performs.

Example answers and how they were marked
Full marks2/2

It focuses the lens and decides when the flash should fire.

Why: Focus the lens (1) and control the flash (1).

Some marks1/2

It controls the zoom and takes a picture when the button is pressed.

Why: Zoom the lens credited (1); 'takes a picture' is not accepted because taking photographs is the function of the camera, which is given in the question, and 'press the button' is the user's action, not a function of the embedded system.

No marks0/2

It takes a picture when the button is pressed and it makes the camera work.

Why: No mark: 'takes a picture' repeats the camera's function given in the question, 'press the button' is an action of the user, and 'makes the camera work' is too vague to name a function.

3Short recall1 markCompression Swap Remove

A company backs up its files to an external hard drive.

Give one reason why the company compresses the files before backing them up.

[1 mark]
Mark scheme

Award one mark for any of the following:

  • More files/data can be stored (in the same storage space) (1)
  • The files take up less storage space (1)
  • The backup is quicker/faster to complete (1)
  • Less data needs to be transferred to the backup device (1)

Do not accept 'makes the files more secure' or 'encrypts the files'.

Example answers and how they were marked
Full marks1/1

The compressed files take up less storage space, so more files can be backed up.

Why: The files take up less storage space (1).

No marks0/1

It reduces the amount of disk fragmentation.

Why: Near-miss: compression does not reduce disk fragmentation.

No marks0/1

It encrypts the files so they are safer if the drive is stolen.

Why: Misconception: compression does not encrypt files, and security is not accepted.

4Describe2 marksTranslators Swap Remove

Source code can contain syntax errors.

Describe how a compiler and an interpreter differ in the way they deal with syntax errors.

[2 marks]
Mark scheme

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

  • The compiler reports all syntax errors after translation has finished (1) whereas the interpreter stops at the first error it finds (1)
  • The interpreter reports a syntax error as soon as it finds one (1) and does not translate/execute any more of the program (1)
  • The compiler continues translating after an error (1) and reports the errors at the end (1)
  • The interpreter stops translating when it reaches an error (1) but the compiler finishes translating before reporting errors (1)

Do not accept answers about fixing/correcting errors or about object code.

Do not award 'the compiler finds more errors' without saying errors are reported at the end.

Example answers and how they were marked
Full marks2/2

A compiler reports all the syntax errors at the end of translation, whereas an interpreter stops and reports the error as soon as it finds one.

Why: Compiler reports errors at the end (1) and interpreter stops/reports at the first error (1).

Some marks1/2

An interpreter stops translating when it finds a syntax error.

Why: Interpreter stops at the first error (1); no comparison with when the compiler reports errors.

No marks0/2

A compiler reports a syntax error immediately, before translating the rest of the program.

Why: Reverses the compiler's behaviour; it finishes translating before reporting errors.

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