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
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
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 or Stuvia-credit 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 Allivia. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.99. You're not tied to anything after your purchase.