fundamentals of data representation

Question 1

what is 0011 1010 in hexadecimal?

Answer 1

3A

Question 2

what is 1101 0011 in decimal?

Answer 2

211

Question 3

what is fd in decimal?

Answer 3

253

Question 4

what is 4b in binary?

Answer 4

01001011

Question 5

what is 20 in binary?

Answer 5

0001 0100

Question 6

what does a binary shift to the left do?

Answer 6

n shifts to the left multiplies the number by 2^n

Question 7

what does a binary shift to the right do?

Answer 7

n shifts to the left divides the number by 2^n

Question 8

how many bits is needed to represent a character in ascii?

Answer 8

seven

Question 9

what are the advantages to unicode over ascii?

Answer 9

unicode allows more characters so is better for languages with special characters or longer alphabets

Question 10

file size ( bytes ) =

Answer 10

image size x colour depth / 8

Question 11

what is a pixel?

Answer 11

a single point in an image

Question 12

colour depth =

Answer 12

bits / pixel

Question 13

what happens to the image if the colour depth is improved?

Answer 13

the size of the file will increase

the quality of the file will increase

Question 14

what is a sample of sound?

Answer 14

a measure of amplitude at one point in time

Question 15

how can the quality of sound improve?

Answer 15

increase the sample rate - number of samples per second ( Hz )
increase the sample resolution - number of bits per sample

Question 16

size of sound sample =

Answer 16

sample rate x sample resolution x number of seconds

Question 17

why is compression useful?

Answer 17

• reduces the amount of space needed to hold a file
• reduces the time it takes to transport the file
• allows large files to be sent over email

Question 18

why does huffman coding allow data to be stored in a smaller place than ascii?

Answer 18

because huffman encodes characters by how frequently they appear, so the characters that are most common require fewer bits to store
- whereas in ascii each character, no matter how common or uncommon needs seven bits

Question 19

what is 11110 01111 00100 11000 00111 in rle?

Answer 19

4 0 2 1 4 0 2 1 1 0 2 1 2 0 3 1 2 0 3 1