2025 AQA AS COMPUTER SCIENCE Paper 2 Question Paper &
Mark Scheme (Merged) Monday 19 May 2025 [VERIFIED]
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
AS
COMPUTER SCIENCE
Paper 2
Monday 19 May 2025 Afternoon Time allowed: 1 hour 30 minutes
Materials
For this paper you must have: For Examiner’s Use
a calculator.
Question Mark
Instructions 1
Use black ink or black ball-point pen. 2
Fill in the boxes at the top of this page.
3
Answer all questions.
You must answer the questions in the spaces provided. Do not write outside 4
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).
Do all rough work in this book. Cross through any work you do not want to 7
be marked. 8
9
Information
The marks for questions are shown in brackets. 10
The maximum mark for this paper is 75. 11
12
Advice
In some questions you are required to indicate your answer by completely 13
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.
7 5 1 6/2
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, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 . 1 Which two of the numbers below belong to the set of numbers represented by ℤ?
Shade two lozenges.
[2 marks]
A 0
B √2
C π
3
D
4
E 998
0 1 . 2 Describe what is meant by the term ‘ordinal number’.
[1 mark]
0 1 . 3 Explain why real numbers are better suited to representing measurements of some
quantities than natural numbers.
[1 mark]
4
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, 3
Do not write
outside the
box
0 2 . 1 How many different values can be represented using one byte?
[1 mark]
0 2 . 2 The bit pattern in Figure 1 represents an 8-bit unsigned binary integer.
Figure 1
0 1 0 0 0 0 1 1
Convert the bit pattern in Figure 1 to decimal.
[1 mark]
0 2 . 3 Show how the 8-bit unsigned binary number 01001111 can be added to the 8-bit
unsigned binary number 00001011 without converting the numbers into decimal.
You must show all your working in binary.
[2 marks]
0 1 0 0 1 1 1 1
+ 0 0 0 0 1 0 1 1
Turn over ►
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, 4
Do not write
outside the
box
0 2 . 4 What are the lowest and highest values that can be represented by a
4-bit two’s complement binary integer?
Give your answers in decimal.
[2 marks]
Lowest
Highest
0 2 . 5 Using 8-bit two’s complement binary, what is the result of subtracting 00110100
from 01101101?
Give your answer in 8-bit two’s complement binary.
You must show all your working in binary.
[3 marks]
0 2 . 6 Represent 5.75 as an 8-bit unsigned fixed point binary number with four bits before
and four bits after the binary point.
[2 marks]
11
for more: tyrionpapers.com
IB/G/Jun25/7516/2
Mark Scheme (Merged) Monday 19 May 2025 [VERIFIED]
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
AS
COMPUTER SCIENCE
Paper 2
Monday 19 May 2025 Afternoon Time allowed: 1 hour 30 minutes
Materials
For this paper you must have: For Examiner’s Use
a calculator.
Question Mark
Instructions 1
Use black ink or black ball-point pen. 2
Fill in the boxes at the top of this page.
3
Answer all questions.
You must answer the questions in the spaces provided. Do not write outside 4
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).
Do all rough work in this book. Cross through any work you do not want to 7
be marked. 8
9
Information
The marks for questions are shown in brackets. 10
The maximum mark for this paper is 75. 11
12
Advice
In some questions you are required to indicate your answer by completely 13
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.
7 5 1 6/2
for more: tyrionp ape rs.c om
IB/G/Jun25/G4002/E11
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 . 1 Which two of the numbers below belong to the set of numbers represented by ℤ?
Shade two lozenges.
[2 marks]
A 0
B √2
C π
3
D
4
E 998
0 1 . 2 Describe what is meant by the term ‘ordinal number’.
[1 mark]
0 1 . 3 Explain why real numbers are better suited to representing measurements of some
quantities than natural numbers.
[1 mark]
4
for more: tyrionpapers.com
IB/G/Jun25/7516/2
, 3
Do not write
outside the
box
0 2 . 1 How many different values can be represented using one byte?
[1 mark]
0 2 . 2 The bit pattern in Figure 1 represents an 8-bit unsigned binary integer.
Figure 1
0 1 0 0 0 0 1 1
Convert the bit pattern in Figure 1 to decimal.
[1 mark]
0 2 . 3 Show how the 8-bit unsigned binary number 01001111 can be added to the 8-bit
unsigned binary number 00001011 without converting the numbers into decimal.
You must show all your working in binary.
[2 marks]
0 1 0 0 1 1 1 1
+ 0 0 0 0 1 0 1 1
Turn over ►
for more: tyrionpapers.com
IB/G/Jun25/7516/2
, 4
Do not write
outside the
box
0 2 . 4 What are the lowest and highest values that can be represented by a
4-bit two’s complement binary integer?
Give your answers in decimal.
[2 marks]
Lowest
Highest
0 2 . 5 Using 8-bit two’s complement binary, what is the result of subtracting 00110100
from 01101101?
Give your answer in 8-bit two’s complement binary.
You must show all your working in binary.
[3 marks]
0 2 . 6 Represent 5.75 as an 8-bit unsigned fixed point binary number with four bits before
and four bits after the binary point.
[2 marks]
11
for more: tyrionpapers.com
IB/G/Jun25/7516/2
