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I declare this is my own work.
A-level
COMPUTER SCIENCE
Paper 2
Time allowed: 2 hours 30 minutes
Materials
For Examiner’s Use
For this paper you must have:
• a calculator. Question Mark
1
Instructions
• Use black ink or black ball-point pen. 2
• Fill in the boxes at the top of this page. 3
• Answer all questions. 4
• You must answer the questions in the spaces provided. Do not write outside
the box around each page or on blank pages. 5
• If you need extra space for your answer(s), use the lined pages at the end of 6
this book. Write the question number against your answer(s). 7
• Do all rough work in this book. Cross through any work you do not want to
8
be marked.
9
Information 10
• The marks for questions are shown in brackets.
11
• The maximum mark for this paper is 100.
12
Advice 13
• In some questions you are required to indicate your answer by completely
shading a lozenge alongside the appropriate answer as shown. TOTAL
• If you want to change your answer you must cross out your original answer as
shown.
• If you wish to return to an answer previously crossed out, ring the answer
you now wish to select as shown.
*JUN227517201*
IB/G/Jun22/E16 7517/2
, 2
Do not write
outside the
Answer all questions. box
0 1 . 1 Describe how a 12-bit unsigned binary integer such as 010010101110 can be
converted directly into hexadecimal.
The method you describe must not involve converting into decimal.
[2 marks]
0 1 . 2 State one reason why hexadecimal is often used in preference to binary.
[1 mark]
3
0 2 . 1 A data communications system uses parallel data transmission.
Describe how parallel data transmission works.
[2 marks]
*02*
IB/G/Jun22/7517/2
, 3
Do not write
outside the
0 2 . 2 State one advantage of serial data transmission over parallel data transmission. box
[1 mark]
0 2 . 3 Shade one lozenge to indicate which of these statements about data communications
systems is false.
[1 mark]
For a particular communications channel, the bit rate can be higher than
A
the baud rate.
B Latency is the rate at which signals on a wire or line can change.
The bandwidth of a transmission medium is the range of signal
C frequencies that the medium can transmit without a significant reduction
in signal strength.
The greater the bandwidth of a transmission medium the higher the bit
D
rate that can be achieved by a communication system using it.
0 2 . 4 State the purpose of the start bit in asynchronous serial transmission.
[1 mark]
0 2 . 5 State the purpose of the stop bit in asynchronous serial transmission.
[1 mark]
6
Turn over ►
*03*
IB/G/Jun22/7517/2
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