AQA A-level COMPUTER SCIENCE Paper 2 QP 2021
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
A-level
COMPUTER SCIENCE
Paper 2
Time allowed: 2 hours 30 minutes
Materials
For this paper you must have:
• a calculator. For Examiner’s Use
Instructions Question Mark
• Use black ink or black ball-point pen. 1
• Fill in the boxes at the top of this page. 2
• Answer all questions.
• You must answer the questions in the spaces provided. Do not write outside 3
the box around each page or on blank pages. 4
• If you need extra space for your answer(s), use the lined pages at the end of 5
this book. Write the question number against your answer(s).
6
• Do all rough work in this book. Cross through any work you do not want to
be marked. 7
8
Information
9
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 100. 10
11
Advice 12
• In some questions you are required to indicate your answer by completely
13
shading a lozenge alongside the appropriate answer as shown.
• If you want to change your answer you must cross out your original answer as 14
shown.
TOTAL
• If you wish to return to an answer previously crossed out, ring the answer
you now wish to select as shown.
*JUN217517201*
IB/G/Jun21/E17 7517/2
, 2
Do not write
outside the
Answer all questions. box
0 1 . 1 A bitmap image is 1000 pixels wide by 800 pixels high.
The image takes up 400 kB of storage space when represented as a bitmap,
excluding metadata.
Calculate the maximum number of different colours that could appear in the image.
You should show your working.
[3 marks]
Answer
*02*
IB/G/Jun21/7517/2
, 3
Do not write
outside the
0 1 . 2 The same image can also be represented using vector graphics. box
The vector graphics representation of the image takes up 2 kB of storage space.
Explain why the amount of storage space taken up by the vector graphics
representation of the image is significantly smaller than the space taken up by the
bitmap representation.
[3 marks]
0 1 . 3 One advantage of vector graphics compared to bitmap graphics is that fewer bytes
are used to represent an image.
State two other advantages of vector graphics compared with bitmap graphics.
[2 marks]
Advantage 1
Advantage 2
8
Turn over for the next question
Turn over ►
*03*
IB/G/Jun21/7517/2
, 4
Do not write
outside the
0 2 Describe what thin-client computing is and explain two reasons why a thin-client box
system might be chosen in preference to a thick-client system.
[3 marks]
3
0 3 A data communications system can transmit four different signals. Each different
signal represents two bits of data.
0 3 . 1 Describe the exact relationship between the bit rate and the baud rate for this
system.
[1 mark]
0 3 . 2 Describe the relationship between the bit rate of the system and the bandwidth of the
transmission medium that the data is transmitted through.
[1 mark]
*04*
IB/G/Jun21/7517/2
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
A-level
COMPUTER SCIENCE
Paper 2
Time allowed: 2 hours 30 minutes
Materials
For this paper you must have:
• a calculator. For Examiner’s Use
Instructions Question Mark
• Use black ink or black ball-point pen. 1
• Fill in the boxes at the top of this page. 2
• Answer all questions.
• You must answer the questions in the spaces provided. Do not write outside 3
the box around each page or on blank pages. 4
• If you need extra space for your answer(s), use the lined pages at the end of 5
this book. Write the question number against your answer(s).
6
• Do all rough work in this book. Cross through any work you do not want to
be marked. 7
8
Information
9
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 100. 10
11
Advice 12
• In some questions you are required to indicate your answer by completely
13
shading a lozenge alongside the appropriate answer as shown.
• If you want to change your answer you must cross out your original answer as 14
shown.
TOTAL
• If you wish to return to an answer previously crossed out, ring the answer
you now wish to select as shown.
*JUN217517201*
IB/G/Jun21/E17 7517/2
, 2
Do not write
outside the
Answer all questions. box
0 1 . 1 A bitmap image is 1000 pixels wide by 800 pixels high.
The image takes up 400 kB of storage space when represented as a bitmap,
excluding metadata.
Calculate the maximum number of different colours that could appear in the image.
You should show your working.
[3 marks]
Answer
*02*
IB/G/Jun21/7517/2
, 3
Do not write
outside the
0 1 . 2 The same image can also be represented using vector graphics. box
The vector graphics representation of the image takes up 2 kB of storage space.
Explain why the amount of storage space taken up by the vector graphics
representation of the image is significantly smaller than the space taken up by the
bitmap representation.
[3 marks]
0 1 . 3 One advantage of vector graphics compared to bitmap graphics is that fewer bytes
are used to represent an image.
State two other advantages of vector graphics compared with bitmap graphics.
[2 marks]
Advantage 1
Advantage 2
8
Turn over for the next question
Turn over ►
*03*
IB/G/Jun21/7517/2
, 4
Do not write
outside the
0 2 Describe what thin-client computing is and explain two reasons why a thin-client box
system might be chosen in preference to a thick-client system.
[3 marks]
3
0 3 A data communications system can transmit four different signals. Each different
signal represents two bits of data.
0 3 . 1 Describe the exact relationship between the bit rate and the baud rate for this
system.
[1 mark]
0 3 . 2 Describe the relationship between the bit rate of the system and the bandwidth of the
transmission medium that the data is transmitted through.
[1 mark]
*04*
IB/G/Jun21/7517/2
