AQA A Level Computer Science

Which regular expression matches the FSM?

• a?bc(dc)*

• a|b(cd)+

• a+bc(dc)?

• a(b|c)d*c*

Select the strings that are matched by the regular expression:

a(b|c)?d

• abcbcbcbcd

• acd

• ad

• acccd

The Caesar cipher is an example of what type of cipher?

• Substitution cipher

• Transposition cipher

• Public key encryption

• Vernam cipher

The letter m has an ascii code of 1101101. As part of a Vernam cipher, the key 0101001 is applied to that letter. What is the resulting ciphertext?

• 1000100

• 0111011

• 1100101

• 1101001

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

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

Which of the following is Nyquist's Theorem?

• e = mc²

• file size = sample res * sample rate

• f_s > 2f_max

Abstraction is the act of...

• Adding extra detail to enable someone else to be able to solve the task without your help

• Removing the detail that is important to solve the task

• Removing all unnecessary detail to focus on what is important to solve the task

• Creating an image that is similar to the object in question in some abstract way

When would you use 'indefinite iteration'?

• When you are unsure about how many times a loop will need to run to satisfy a condition

• When you know exactly how many times you need to run the loop in the algorithm

• When you want a different piece of code to run depending upon the value of a variable or condition