Y10 1.2.1 Character Sets

Why do computers use character sets?

• To make graphics look sharper

• To turn letters and symbols into binary codes

• To speed up the CPU

• To reduce storage space

Answer explanation

Explanation: Computers only understand binary. Character sets provide binary codes for text so it can be stored and displayed.

What problem would computers face without character sets?

• They could not connect to the internet

• They could not store sound or video

• They could not understand or share text

• They would run slower

Answer explanation

Explanation: Without character sets, there would be no standard way to represent human-readable text in binary.

How many characters does standard ASCII represent, and why does it use 7 bits instead of 8?

• 64 characters, to save memory

• 128 characters, leaving the 8th bit free for error checking

• 256 characters, using all 8 bits

• 512 characters, using extra storage

Answer explanation

Explanation: ASCII uses 7 bits (128 characters). The extra 8th bit was kept free for error detection in communication.

What are control characters in ASCII used for?

• Printing emojis

• Controlling devices or text layout

• Adding accented letters

• Saving storage space

Answer explanation

Explanation: ASCII codes 0–31 are control characters, used for things like line breaks or signals to printers.

How many characters does Extended ASCII represent, and why was it created?

• 128 characters, to keep things simple

• 256 characters, to add accented letters and symbols

• 512 characters, for faster processing

• 1024 characters, for all world languages

Answer explanation

Explanation: Extended ASCII uses 8 bits (256 codes). It added more characters like accented letters and graphics.

Why was Unicode created?

• To replace binary numbers with letters

• To give every language and writing system a code

• To make ASCII faster

• To reduce file sizes

Answer explanation

Explanation: ASCII couldn’t cover all world languages. Unicode is a universal standard for every writing system.

What exists in Unicode after the first 128 codes?

• Nothing, it stops at 128

• Only extra emojis

• Thousands of codes for world languages, symbols, and emojis

• Random unused codes

Answer explanation

Explanation: The first 128 Unicode codes match ASCII. After that, Unicode includes thousands of codes for languages, scripts, and symbols.

Why can Unicode use up to 4 bytes for one character?

• To make files larger

• To support billions of possible unique characters

• To speed up the CPU

• To make ASCII compatible with it.

Answer explanation

Explanation: Unicode allows up to 32 bits (4 bytes) so it can represent characters from all languages, plus emojis and symbols.

Why do UTF-8 and UTF-16 use a range of bytes instead of a fixed amount?

• To waste storage space

• To allow different fonts

• To save storage for simple characters and expand for complex ones

• To make ASCII faster

Answer explanation

Explanation: UTF-8 uses 1–4 bytes, UTF-16 uses 2 or 4 bytes. This variable length saves space for common English characters but can handle rarer ones too.

How does text storage compare between ASCII and Unicode?

• ASCII is always bigger

• ASCII uses 1 byte per character, Unicode uses 1–4 bytes

• Both always use the same size

• Unicode always saves space

Answer explanation

Explanation: ASCII is fixed at 1 byte per character. Unicode varies between 1 and 4 bytes depending on the encoding and character.