Memory & StorageExam Tips

Exam Tips - Character Sets

Part of Character SetsGCSE Computer Science

This exam tips covers Exam Tips - Character Sets within Character Sets for GCSE Computer Science. Revise Character Sets in Memory & Storage for GCSE Computer Science with 15 exam-style questions and 18 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 9 of 10 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.

Topic position

Section 9 of 10

Practice

15 questions

Recall

18 flashcards

Exam Tips - Character Sets

Most common exam questions:

  • "What is ASCII?" → Character set with 128 characters (7-bit), covers English alphabet, numbers, punctuation
  • "Why use Unicode?" → Covers ALL languages and symbols (143,000+ characters), international support, emoji
  • "ASCII code for 'A'?" → 65 (memorize this!)
  • "Difference UTF-8 vs UTF-16?" → UTF-8 uses 1-4 bytes (efficient for English), UTF-16 uses 2-4 bytes (efficient for Asian languages)
  • "How many bytes for ASCII character?" → 1 byte

Key facts to memorize:

  • ASCII: 7-bit (128 characters), English only, 1 byte per character
  • Extended ASCII: 8-bit (256 characters), accented letters
  • Unicode: 143,859 characters, all languages, UTF-8/16/32 encodings
  • UTF-8: 1-4 bytes, most common, web standard
  • Common codes: 'A'=65, 'a'=97, '0'=48, space=32

Common mistakes to avoid:

  • Confusing character set (Unicode) with encoding (UTF-8) - they're related but different!
  • Saying ASCII is 8-bit - NO! Standard ASCII is 7-bit (128 characters)
  • Thinking Unicode uses more space - depends on encoding! UTF-8 is same as ASCII for English
  • Mixing up 'A' (65) and 'a' (97) - uppercase ≠ lowercase

Keep building this topic

Read this section alongside the surrounding pages in Character Sets. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Character Sets

How many bits does standard ASCII use to represent each character?

  • A. 4 bits
  • B. 7 bits
  • C. 8 bits
  • D. 16 bits
1 markfoundation

Explain why using Unicode to store a text file produces a larger file than using ASCII to store the same text.

3 marksstandard

Quick Recall Flashcards

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