A-level
COMPUTER SCIENCE
Paper 2
Time allowed: 2 hours 30 minutes
Materials
For this paper you must have:
• a calculator.
Instructions
• Use black ink or black ball-point pen.
• Fill in the boxes at the top of this page.
• Answer all questions.
• You must answer the questio...
Time allowed: 2 hours 30 minutes
Materials
For Examiner’s Use
For this paper you must have:
a calculator. Questio Mark
n
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 4
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).
Do all rough work in this book. Cross through any work you do 7
not want to be marked. 8
9
Information
10
The marks for questions are shown in brackets.
The maximum mark for this paper is 100. 11
12
Advice 13
In some questions you are required to indicate your answer by
completely shading a lozenge alongside the appropriate answer TOTAL
as shown.
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.
1
, 2
Do not write
outside the
Answer all box
questions.
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 box
transmission.
[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
A
higher than 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
D higher the bit 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
*03
IB/G/
* Jun22/7517/2
, 4
Do not write
outside the
Turn over ►
*03
IB/G/
* Jun22/7517/2
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller bestgradesA33. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £12.20. You're not tied to anything after your purchase.
