Question 1: Explain in your own words what data compression is and why it is useful.

Answer: Data compression is the process of reducing the size of data files so they take up less space. It is useful because it saves storage space and makes transferring files faster.

Question 2: Describe a situation where data compression might be especially helpful.

Answer: Data compression is helpful when sending large video files over the internet, as it reduces the file size and makes upload and download faster.

Question 3: Name two common types of data compression: one that reduces file size without losing any information and one that may lose some information.

Answer: Lossless compression (no data lost), such as ZIP files, and lossy compression (some data lost), such as JPEG images.

Question 4: Complete the following truth table for an AND gate: | Input A | Input B | Output | |---------|---------|--------| | 0 | 0 | | | 0 | 1 | | | 1 | 0 | | | 1 | 1 | |

Answer: 0, 0, 0, 1

Question 5: Draw a logic circuit that shows an AND gate connected to two inputs. Label the inputs as A and B, and the output as Q.

Answer: A correct sketch would show two lines entering an AND gate (a D-shaped symbol), with the output line labeled Q. Inputs A and B connect to the two lines entering the gate.

Question 6: Explain how lossless compression works and give one example of a file type that uses it.

Answer: Lossless compression reduces file size by finding patterns and repeating data, which can be reconstructed exactly later. An example is a ZIP file.

Question 7: Sketch a simple example of how data can be compressed using run-length encoding (RLE). In your sketch, show a row of repeated letters and how it would be stored after compression.

Answer: A row like 'AAAABBBCCDAA' would be compressed as '4A3B2C1D2A', showing the count and the character.

Question 8: List two advantages and one disadvantage of lossy compression.

Answer: Advantages: reduces file size significantly, and maintains acceptable quality for images and audio. Disadvantage: some original data is lost, so quality cannot be restored perfectly.

Question 9: Describe what happens during the process of decompressing a file that has been compressed using ZIP compression.

Answer: During decompression, the ZIP file is opened and the data is reconstructed to its original form, restoring all the original information exactly.

Question 10: Draw a simple diagram that shows the difference between lossless and lossy compression, using two boxes labeled 'Original Data' and 'Compressed Data'.

Answer: A correct sketch would show 'Original Data' being reduced to 'Compressed Data' in two ways: one with an arrow labeled 'Lossless' indicating exact reconstruction, and one with an arrow labeled 'Lossy' indicating some loss of data or quality.