Starter quiz
- What is a digit of a binary number that can only be 1 or 0 called?
- 'bit' ✓
- What does a character set do?
- stores images
- records sound
- matches characters to unique binary sequences ✓
- creates animations
-
- Match the term with its description:
- information⇔data that has been processed to provide meaning ✓
- binary digit (bit)⇔a digit of a binary number that can only be 1 or 0 ✓
- ASCII⇔uses 8 bits per character ✓
- Unicode⇔uses up to 32 bits per character ✓
- Why do computers use binary sequences?
- to simplify calculations
- to save space
- to increase speed
- to represent all data and instructions ✓
-
- How many different characters can 8-bit ASCII represent?
- 64
- 128
- 256 ✓
- 512
-
- What is the main advantage of Unicode over ASCII?
- it uses fewer bits
- it can represent more characters ✓
- it is faster to process
- it is easier to understand
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Exit quiz
- Put these quantities of bytes into order, smallest to largest:
- 1⇔byte
- 2⇔kilobyte
- 3⇔megabyte
- 4⇔gigabyte
- 5⇔terabyte
- 6⇔petabyte
- What is a byte?
- a single bit
- a kind of software
- a group of 8 bits ✓
- a type of character
-
- How many bits does ASCII use per character?
- 4 bits
- 8 bits ✓
- 16 bits
- 32 bits
-
- How does Unicode differ from ASCII?
- Unicode is only for numbers
- Unicode uses more bits to represent characters ✓
- Unicode is a type of image format
- Unicode is faster to process
-
- If a text file contains 100 characters, what is the file size in bits using ASCII encoding?
- '800' ✓
- A text document has 50 characters. Calculate the file size in bytes when using 32-bit Unicode encoding.
- '200' ✓
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- A byte is the equivalent of 8 bits.
- Large numerical quantities can be summarised using number prefixes.
- Different text encoding schemes use different amounts of bits to represent each character.
- File size is the measure of how much binary data a file contains.
Common misconception
The same text entered into two separate text files will always result in the same file size.
How the text has been encoded will affect the file size of a text file. ASCII uses 8 bits per character whereas Unicode uses up to 32 bits. Therefore the choice of character encoding affects the overall file size of the same text.
Keywords
Byte - a group of 8 bits
Number prefix - a word used in front of a number to represent a multiple of that number
Encoding - putting a sequence of characters into an agreed format
File size - a measure of how much binary data a file contains
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