83. AQA GCSE (8525) SLR13 – 3.3 Compression

What is the primary purpose of compression?

• To reduce the size of a file

• To enhance the quality of files

• To change the file format

• To increase the download time

Answer explanation

The primary purpose of compression is to reduce the size of a file, making it easier to store and transfer while maintaining its content.

Why is compression particularly useful on mobile phones?

• To improve screen resolution

• To increase battery life

• To store more apps and photos

• To make the phone lighter

Answer explanation

Compression on mobile phones is particularly useful to store more apps and photos by reducing the size of data, allowing for more storage capacity.

What is a benefit of smaller file sizes for internet use?

• They reduce the quality of videos

• They make streaming possible

• They are slower to download

• They require more storage

Answer explanation

Smaller file sizes make streaming possible by reducing the amount of data that needs to be transferred, leading to faster loading times and smoother playback.

What must often be done to compressed files before they can be used?

• They must be shared

• They must be deleted

• They must be uncompressed

• They must be colored

Answer explanation

Compressed files must be uncompressed before they can be used, not shared, deleted, or colored.

Which type of compression affects the quality of the image?

• GIF compression

• Lossy compression

• JPEG compression

• Lossless compression

Answer explanation

Lossy compression reduces image quality by removing some data during the compression process.

What is an acceptable compromise in lossy compression?

• Use of more colors

• Increased file size

• Decreased download time

• A little loss of quality

Answer explanation

An acceptable compromise in lossy compression involves a little loss of quality to achieve reduced file size or download time while maintaining a satisfactory level of visual or auditory fidelity.

What type of compression does not lose any data?

• Lossy compression

• Lossless compression

• GIF compression

• JPEG compression

Answer explanation

Lossless compression retains all data during the compression process, ensuring no loss of information.

Which images are suitable for lossless compression?

• Full-color photographs

• All images

• Cartoons and clip arts

• Videos

Answer explanation

Cartoons and clip arts are suitable for lossless compression because they have large areas of solid colors and sharp edges, making them easier to compress without losing quality.

Why can't lossy compression be used on executable files?

• It loses essential data

• It is not secure

• It changes the file format

• It increases the file size

Answer explanation

Lossy compression cannot be used on executable files because it loses essential data, which can corrupt the file and make it unusable.

What does compression reduce in a file?

• Functionality

• Resolution

• Number of bits

• Color quality

Answer explanation

Compression reduces the number of bits in a file by encoding data more efficiently, resulting in a smaller file size.