Back to the full dot-point answer
SingaporeComputer ScienceQuick questions
Data Representation
Quick questions on Representing text, sound and images explained: O-Level Computing
6short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What are representing text with character codes?Show answer
A computer cannot store a letter directly, so each character is given an agreed number by a character set. The most common is ASCII, which uses or bits per character. For example, the code for 'A' is , and the codes for the other capitals follow in order ('B' is , 'C' is , and so on). Lower-case letters start at 'a' = .
What is representing sound by sampling?Show answer
Sound is a continuous wave, but a computer needs discrete numbers. It measures (samples) the height of the wave many times per second and stores each measurement as a binary number. Two settings control the quality:
What are representing images with pixels?Show answer
A digital image is a grid of tiny dots called pixels. Each pixel stores a colour as a binary number. The number of bits used per pixel is the colour depth:
What is q1?Show answer
State how many colours a pixel can be at a colour depth of bits. [2 marks]
What is q2?Show answer
Explain why ASCII is described as a standard. [2 marks]
What is q3?Show answer
State two settings that affect the quality and file size of a digital sound recording. [2 marks]
Have a question we have not covered?
This dot-point answer is short enough that we have not extracted many short questions yet. Read the full dot-point answer or ask Mo, our study assistant, in the chat for follow ups.