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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 · 8 marks

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1Multiple choice1 markImages Swap Remove

Two images are displayed at the same physical size. Image A has a higher resolution than image B.

Identify what this means.

[1 mark]
  • AImage A has more bits per pixel
  • BImage A has more colours
  • CImage A has more pixels per inch
  • DImage A uses less storage
Mark scheme
  • C Image A has more pixels per inch (1)
  • The only correct answer is C. The correct answer is more pixels per inch.
  • A is not correct because bits per pixel is the colour depth
  • B is not correct because more colours is caused by a higher colour depth, not a higher resolution
  • D is not correct because a higher resolution usually needs more storage, not less
Example answers and how they were marked
Full marks1/1

C Image A has more pixels per inch

Why: Correct option; resolution is the concentration of pixels, such as pixels per inch (1).

No marks0/1

B Image A has more colours

Why: More colours is an effect of colour depth, not resolution; no mark.

No marks0/1

A Image A has more bits per pixel

Why: Bits per pixel is the colour depth, not the resolution; no mark.

2Describe2 marksTranslators Swap Remove

A high-level program must be translated into machine code before it can be run.

Describe how a compiler and an interpreter differ in when the translated code is executed.

[2 marks]
Mark scheme

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

  • The interpreter executes each line as soon as it has been translated (1) so translation and execution happen together/at the same time (1)
  • The compiler translates the whole program first (1) and the machine code is run later/separately (1)
  • The interpreter translates the code and runs it while the program is running (1) whereas the compiler does not run the code it produces (1)
  • The compiler produces translated code that is executed only after all the translation has finished (1) but the interpreter executes each line immediately (1)

Allow 'translates one line at a time' where it is linked to executing each line immediately.

Do not accept answers that only state that a compiler is faster/an interpreter is slower, without reference to when execution happens.

Do not accept answers that only give object code, error reporting or portability, without reference to when execution happens.

Do not accept the compiler executing the program as it translates it.

Example answers and how they were marked
Full marks2/2

The compiler translates the code first and the program is executed afterwards, but the interpreter executes each line as soon as it has been translated.

Why: Compiler translates the whole program first and it is executed afterwards (1) and interpreter executes each line as soon as it is translated (1).

Some marks1/2

The interpreter executes each line immediately after translating it.

Why: Correct interpreter timing (1); no comparison with when the compiler's translated code is executed.

No marks0/2

The compiler executes the program line by line as it translates it.

Why: Reverses the two translators; a compiler does not execute the program it translates, so no mark.

3Explain2 marksProtocols & Layers Swap Remove

Email protocols are used when an email is sent and received.

Explain the role of SMTP when an email is sent.

[2 marks]
Mark scheme

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

  • Sends outgoing email from the client to the mail server (1) so it can be forwarded/relayed to the recipient's mail server (1)
  • Transfers email between mail servers (1) so it reaches the destination server (1)
  • Pushes/sends the email message (1) because it handles outgoing mail while POP3/IMAP handle incoming mail (1)

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

Do not accept receiving/downloading email or storing email on the server, which is POP3/IMAP.

Example answers and how they were marked
Full marks2/2

SMTP sends the email from the sender's computer to the mail server (1) so it can be forwarded on to the recipient's mail server (1).

Why: Linked point (1) and reason (1): sends to the mail server so it can be forwarded.

Some marks1/2

SMTP is used to send emails (1).

Why: Role (1) identified, but no linked reason or expansion of what sending involves.

No marks0/2

SMTP downloads the email to the recipient's device (0) so they can read it.

Why: Downloading email is the role of POP3/IMAP, not SMTP, so no credit is given.

4Calculate3 marksAdding Binary Numbers Swap Remove

Binary patterns can represent numbers.

(a)

Complete the table to show the 8-bit result of the binary addition.

[2 marks]
1286432168421
11011011
11011100
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 1011 (1)
  • 0111 (1)

0 marks if the response is not 8-bit binary.

Ignore a carry shown beyond the eighth bit.

Example answers and how they were marked
Full marks2/2

1011 0111

Why: 219 + 220 = 439, which needs 9 bits; the 8 bits that are kept are both correct (2).

Some marks1/2

0000 0111

Why: Forgets to carry the 1s. The second nibble is correct (1); the first is not.

No marks0/2

1101 1111

Why: Never carries. Neither nibble is correct.

(b)

State the name of the error that occurs when this addition is carried out.

[1 mark]
Mark scheme

Award one mark for:

  • overflow (error) (1)
Example answers and how they were marked
Full marks1/1

Overflow

Why: The result needs more bits than are available (1).

No marks0/1

Underflow

Why: A near miss: the result is too big for 8 bits, not too small.

No marks0/1

A syntax error

Why: A syntax error is a mistake in a program's code, not in arithmetic.

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