Starter quiz
- What is the smallest unit of data in a computer system?
- 'bit' ✓
- What is the term for the number of pixels in an image?
- 'resolution' ✓
- What happens when you increase the resolution of an image?
- the file size decreases
- the image quality improves ✓
- the image becomes monochrome
- the colours change
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- What does colour depth refer to?
- the number of bits used to represent a colour ✓
- the brightness of an image
- the number of colours in an image
- the size of an image
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- What is the effect of using a higher sample resolution for sound files?
- lower quality
- smaller file size
- more accurate sound representation ✓
- fewer sound channels
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- How does the size of a file affect its transfer speed over a network?
- file size does not affect transfer speed
- larger files always transfer at the same speed as smaller files
- larger files transfer faster than smaller files
- larger files transfer slower than smaller files ✓
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Exit quiz
- What type of compression permanently removes data?
- 'lossy' ✓
- What is the term for compression that retains all original data?
- 'lossless' ✓
- Match the terms with their definitions.
- compression⇔reducing file size ✓
- decompression⇔restoring file to original size ✓
- lossy compression⇔permanently removes data ✓
- lossless compression⇔retains all original data ✓
- file size⇔the amount of data a file contains ✓
- Which compression method is typically used for audio and video files to save space?
- lossy ✓
- lossless
- temporary
- permanent
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- How does compression affect file transfer speeds?
- it slows them down
- it speeds them up ✓
- it has no effect
- it makes them unpredictable
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- What is a key feature of lossless compression?
- it reduces quality
- it increases file size
- it retains all original data without quality loss ✓
- it permanently removes data
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Compression is used to reduce the size of digital files.
- Lossy and lossless compression affects digital files.
- Using compressed files has both benefits and drawbacks for the use and transfer of file.
Common misconception
Compression always reduces quality or that compressed files are always lower quality than uncompressed files.
Lossless compression retains all original data by finding and storing repeated patterns more efficiently.
Keywords
Lossy compression - a method where data is permanently lost during the compression process and must be approximated when the file is decompressed
Lossless compression - a method of compression where no data is permanently lost during the process
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