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WorksheetsCoding Systems 1 - AQA A Level Computer Science
Total questions: 10
Worksheet time: 5mins
How many different combinations of bit patterns can be represented using ASCII?
127
128
255
256
The ASCII value for the letter 'a' in binary is 110 0001. What is the binary ASCII value for the letter 'e'?
110 0010
110 0100
110 0101
110 0110
The bit pattern 0110001 is sent with an even parity bit in the MSB position.
Which of these is the bit pattern receivedt?
00110001
10110001
01100011
01100010
Data is received that had been sent using majority voting. The received bit pattern is 100 000 011 111.
What bit pattern does the receiving device interpret this as?
0011
1010
0001
1001
The image shows how a modulo 11 check digit can be calculated.
Find the check digit for the string of digits 1 2 3 4 using modulo 11.
1
2
3
4
5
The bitmap image of the lemming is 6 pixels by 10 pixels. There are 16 available colours for each pixel. Calculate the file size of the image (not including any metadata) in bytes.
30
120
22.5
60
Which of these are advantages of vector graphics over bitmap graphics?
Can be rescaled without distortion
(Usually) a smaller file size
Ideal for photographic images
Each pixel can be modified individually
An image of a circle is to be stored as a vector graphic.
Which of these properties must be stored?
Location of the circle (e.g. its centre)
Radius or diameter of the circle
The fill colour
The colour and thickness off its outline
The numbers of bits used to represent its colour
Bitmap files have larger file sizes than that calculated by resolution and colour depth. What is the reason for this?
Extra bits per pixel are stored in case more colours are required
To allow accurate rescaling of the image
Lossless compression
Metadata
Why was Unicode introduced to represent characters in binary?
ASCII doesn't allow enough combinations to represent characters from other languages
Universal international coding system required due to world wide use of digital communication
To decrease the storage requirements of text files
Resolve confusion between upper and lower case characters
