Convert 250 000 MB to terabytes. [1]
Convert 250 000 MB to terabytes. [1]
Tap/click to reveal 0.25 TB ✓
Describe how binary is used to represent data in computers. [2]
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Computers are made up of logic circuits, ✓
which use the electricity being on or off as representing a 1 or a 0. ✓
Convert 12310 into binary. [1]
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11110112 ✓
Convert EA16 into decimal. [1]
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23410 ✓
How many 8-bit binary numbers are there? [1]
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28 = 256 ✓
Right-shift 110001012 by two places. [1]
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1100012 ✓
Define the term "character set". [2]
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A collection of characters ✓
that a computer can recognise from their binary representation. ✓
Unicode uses 32 bits per character.
James claims that Unicode can represent 4 to 5 times as many characters as 7-bit ASCII.
Explain whether or not James is correct. [3]
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James is wrong. ✓
ASCII can represent 27 = 128 characters, ✓
but Unicode could represent 232 ≈ 4.3 billion characters. ✓
If, in 7-bit ASCII, the character "x" is represented by the binary code 111 10002, what binary code represents the character "r"? [1]
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111 00102 ✓
State how changing the colour depth affects the quality of an image. [1]
Tap/click to reveal Increasing the colour depth increases the quality of an image. ✓
State how changing the sampling rate affects the quality of an audio file. [1]
Tap/click to reveal Increasing the sampling rate increases the quality of an audio file. ✓
Give one benefit of using lossy compression instead of lossless compression. [1]
Tap/click to reveal The file size will probably be smaller. ✓
Use RLE to encode the string abbcccddd. [1]
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(1, a) (2, b) (3, c) (3, d) ✓
Could changing the order of the characters inside a string affect the length of the output of RLE? What about for Huffman Coding? [2]
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RLE: yes ✓ (because if you put long runs of identical characters next to each other the output will be shorter)
Huffman Coding: no ✓ (because no matter how you arrange the characters, the length of the binary code for each specific character is fixed)