Oxford Cambridge and RSA
Monday 12 May 2025 – Afternoon
GCSE (9–1) Computer Science
J277/01 Computer Systems
Time allowed: 1 hour 30 minutes
Do not use:
* 1 3 7 9 9 9 3 0 5 8 *
• a calculator
* J 2 7 7 0 1 *
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
INFORMATION
• The total mark for this paper is 80.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in question marked with an asterisk (*).
• This document has 16 pages.
ADVICE
• Read each question carefully before you start your answer.
© OCR 2025 [601/8355/X] OCR is an exempt Charity
DC (ST) 336001/5 Turn over
, 2
1 A student is creating a presentation containing images and sound.
(a) One of the files is an audio recording.
Complete the description of how a computer stores sound. Fill in the gaps using the given list of
terms. Not all terms will be used.
analogue colour depth higher repeated smaller
binary digital lower sample rate unique
bit depth height measuring sampling
byte hertz recording seconds
An ..................................................................... sound wave needs to be converted into a digital
sound wave.
Sound ..................................................................... is when the amplitude of the sound wave is
measured at set intervals.
The ..................................................................... is the number of times a second the sound wave
is measured. This is given in Hertz.
Each amplitude is given a ..................................................................... binary number. The
number of bits allocated to each sample is the ..................................................................... .
The ..................................................................... the number of bits, the wider the number of
amplitudes can be measured.
[6]
© OCR 2025
, 3
(b) The student creates 10 bitmap images using a computer.
Each image has a colour depth of 8-bits and a resolution of 800 × 500 pixels.
(i) Define the term pixel.
..........................................................................................................................................................
..................................................................................................................................................... [1]
(ii) Calculate the total file size of the 10 images in kilobytes.
Show your working out.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
File size: ......................................... kilobytes
[2]
(iii) State the minimum number of bits that will be needed to represent 240 different colours.
..................................................................................................................................................... [1]
(c) The student wants to use a secondary storage device to move their files to their home computer.
Identify whether the student should use an optical or solid-state type of secondary storage
device. Justify your choice.
Optical or solid-state ...........................................................
Justification ......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..................................................................................................................................................... [4]
© OCR 2025 Turn over
Monday 12 May 2025 – Afternoon
GCSE (9–1) Computer Science
J277/01 Computer Systems
Time allowed: 1 hour 30 minutes
Do not use:
* 1 3 7 9 9 9 3 0 5 8 *
• a calculator
* J 2 7 7 0 1 *
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
INFORMATION
• The total mark for this paper is 80.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in question marked with an asterisk (*).
• This document has 16 pages.
ADVICE
• Read each question carefully before you start your answer.
© OCR 2025 [601/8355/X] OCR is an exempt Charity
DC (ST) 336001/5 Turn over
, 2
1 A student is creating a presentation containing images and sound.
(a) One of the files is an audio recording.
Complete the description of how a computer stores sound. Fill in the gaps using the given list of
terms. Not all terms will be used.
analogue colour depth higher repeated smaller
binary digital lower sample rate unique
bit depth height measuring sampling
byte hertz recording seconds
An ..................................................................... sound wave needs to be converted into a digital
sound wave.
Sound ..................................................................... is when the amplitude of the sound wave is
measured at set intervals.
The ..................................................................... is the number of times a second the sound wave
is measured. This is given in Hertz.
Each amplitude is given a ..................................................................... binary number. The
number of bits allocated to each sample is the ..................................................................... .
The ..................................................................... the number of bits, the wider the number of
amplitudes can be measured.
[6]
© OCR 2025
, 3
(b) The student creates 10 bitmap images using a computer.
Each image has a colour depth of 8-bits and a resolution of 800 × 500 pixels.
(i) Define the term pixel.
..........................................................................................................................................................
..................................................................................................................................................... [1]
(ii) Calculate the total file size of the 10 images in kilobytes.
Show your working out.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
File size: ......................................... kilobytes
[2]
(iii) State the minimum number of bits that will be needed to represent 240 different colours.
..................................................................................................................................................... [1]
(c) The student wants to use a secondary storage device to move their files to their home computer.
Identify whether the student should use an optical or solid-state type of secondary storage
device. Justify your choice.
Optical or solid-state ...........................................................
Justification ......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..................................................................................................................................................... [4]
© OCR 2025 Turn over
