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Representing Text, Sound, Images and Storage: Question 1

Syllabus 1.2

Multiple choice 1 mark

A website developer is choosing a character set to store customer reviews that may include text in several different languages and emoji symbols.

Which statement about the ASCII and Unicode character sets is correct?

Choose an answer to check it, then compare with the worked solution below.
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Worked solution

Why the other options are wrong

  • (A) is incorrect: Unicode covers many more characters and symbols than ASCII, not fewer.
  • (B) is incorrect: using more bits per character is exactly what lets Unicode cover so many extra characters; it does not use fewer bits than ASCII.
  • (D) is incorrect: ASCII typically uses fewer bits per character than Unicode, so the two character sets are not equal in this way.

Why C is correct

Text is converted to binary using a character set, which assigns a unique binary code to every character it supports. ASCII is an older character set that can represent a comparatively small number of characters, mainly the basic Latin alphabet, digits and punctuation. Unicode is a newer, much larger character set: it can represent characters and symbols from many of the world’s written languages, plus symbols such as emojis, that ASCII cannot represent at all. To fit this much larger range of characters, each character in Unicode needs more bits than a character stored using ASCII.

Final answer

C. Unicode represents a far wider range of characters and symbols (including different languages and emojis) than ASCII, using more bits per character to do so.