Cambridge IGCSE Computer Science
0948/0478 Exam Questions Answered (latest
update 2023/2024/2025)
what is a character set - Correct Answer ✅A representation
of characters as numbers. Each character gets a number.
Unicode and ASCII are character sets.
what is ASCII code - Correct Answer ✅American Standard
Code for Information Interchange - it is used to represent the
english alphabet and encodes 128 characters into 7-bit
binary codes
What is Unicode? - Correct Answer ✅Unicode is used for
internal representation of characters and strings and it uses
16 bits to represent each other.
what are the 2 differences between ASCII code and unicode -
Correct Answer ✅- unicode allows for a greater range of
characters including different languages than ASCII
- unicode requires more bits per character than ASCII
how does a computer represent sound - Correct Answer ✅a
sound wave is sampled so it can be stored and processed by
a computer
,Cambridge IGCSE Computer Science
0948/0478 Exam Questions Answered (latest
update 2023/2024/2025)
What is sampling? - Correct Answer ✅when an analogue to
digital converter converts sound into a digital form
what is the sample rate - Correct Answer ✅the number of
sample taken in a second
what is the sample resolution - Correct Answer ✅Number
of bits per sample
what happens as the sample rate and resolution increases -
Correct Answer ✅the accuracy of the recording and the file
size increases
What is an image? - Correct Answer ✅An image is a series
of pixels that are converted to binary, which is processed by a
computer
what is the resolution of an image - Correct Answer ✅the
number of pixels in the image
,Cambridge IGCSE Computer Science
0948/0478 Exam Questions Answered (latest
update 2023/2024/2025)
what us the colour depth of an image - Correct Answer
✅the number of bits used to represent each colour
what happens as resolution and colour depth increases -
Correct Answer ✅the file size and quality of the image
increases
how do you calculate file size of an image file - Correct
Answer ✅resolution (width x height) x bit depth
how do you calculate file size of a sound file - Correct
Answer ✅sampling frequency x bit depth x length
what are 3 advantages of compression - Correct Answer ✅-
less bandwidth required
- less storage space required
- shorter transmission time
, Cambridge IGCSE Computer Science
0948/0478 Exam Questions Answered (latest
update 2023/2024/2025)
what is lossy compression - Correct Answer ✅Compression
in which some of the information is permanently removed.
e.g. reducing resolution, colour depth or reducing sample rate
what is lossless compression - Correct Answer ✅Making
the size of a file smaller without permenantly losing any of
the information in the file.
what happens to data to be transmitted - Correct Answer
✅data is broken down into packets to be transmitted
what is the structure of a data packet - Correct Answer ✅a
data packet contains a packet header a payload and a trailer
What is a payload? - Correct Answer ✅the actual data
being sent
what is a trailer - Correct Answer ✅the end bit of a data
being sent
0948/0478 Exam Questions Answered (latest
update 2023/2024/2025)
what is a character set - Correct Answer ✅A representation
of characters as numbers. Each character gets a number.
Unicode and ASCII are character sets.
what is ASCII code - Correct Answer ✅American Standard
Code for Information Interchange - it is used to represent the
english alphabet and encodes 128 characters into 7-bit
binary codes
What is Unicode? - Correct Answer ✅Unicode is used for
internal representation of characters and strings and it uses
16 bits to represent each other.
what are the 2 differences between ASCII code and unicode -
Correct Answer ✅- unicode allows for a greater range of
characters including different languages than ASCII
- unicode requires more bits per character than ASCII
how does a computer represent sound - Correct Answer ✅a
sound wave is sampled so it can be stored and processed by
a computer
,Cambridge IGCSE Computer Science
0948/0478 Exam Questions Answered (latest
update 2023/2024/2025)
What is sampling? - Correct Answer ✅when an analogue to
digital converter converts sound into a digital form
what is the sample rate - Correct Answer ✅the number of
sample taken in a second
what is the sample resolution - Correct Answer ✅Number
of bits per sample
what happens as the sample rate and resolution increases -
Correct Answer ✅the accuracy of the recording and the file
size increases
What is an image? - Correct Answer ✅An image is a series
of pixels that are converted to binary, which is processed by a
computer
what is the resolution of an image - Correct Answer ✅the
number of pixels in the image
,Cambridge IGCSE Computer Science
0948/0478 Exam Questions Answered (latest
update 2023/2024/2025)
what us the colour depth of an image - Correct Answer
✅the number of bits used to represent each colour
what happens as resolution and colour depth increases -
Correct Answer ✅the file size and quality of the image
increases
how do you calculate file size of an image file - Correct
Answer ✅resolution (width x height) x bit depth
how do you calculate file size of a sound file - Correct
Answer ✅sampling frequency x bit depth x length
what are 3 advantages of compression - Correct Answer ✅-
less bandwidth required
- less storage space required
- shorter transmission time
, Cambridge IGCSE Computer Science
0948/0478 Exam Questions Answered (latest
update 2023/2024/2025)
what is lossy compression - Correct Answer ✅Compression
in which some of the information is permanently removed.
e.g. reducing resolution, colour depth or reducing sample rate
what is lossless compression - Correct Answer ✅Making
the size of a file smaller without permenantly losing any of
the information in the file.
what happens to data to be transmitted - Correct Answer
✅data is broken down into packets to be transmitted
what is the structure of a data packet - Correct Answer ✅a
data packet contains a packet header a payload and a trailer
What is a payload? - Correct Answer ✅the actual data
being sent
what is a trailer - Correct Answer ✅the end bit of a data
being sent
