2.1.4 Data Representation

Question 1

How many bits in a nibble?

Answer 1

4 bits are in a nibble

Question 2

How many bits are in a byte?

Answer 2

8 bits are in a byte

Question 3

How many byte in a kilobyte (Kb)?

Answer 3

1024/1000 bytes in a kilobyte

Question 4

How many kilobytes in a megabyte (Mb)?

Answer 4

1024/1000 kilobytes in a megabyte

Question 5

How many megabytes in a gigabyte (Gb)?

Answer 5

1024/1000 megabytes in a gigabyte

Question 6

How many gigabytes in a terabyte?

Answer 6

1024/1000 gigabytes in a terbyte

Question 7

What base number is binary?

Answer 7

Binary is a base 2 number system

Question 8

What is ASCII? and what does it do?

Answer 8

Its the American Standard Code for Information Exchange. It turns the binary representation into a letter (based on the English alphabet)

Question 9

What is Hexadecimal?

Answer 9

A base 16 number system used to make binary easier to understand, but has to be translated for computers to understand

Question 10

What is hexadecimal used for?

Answer 10

Colour referencing (red, blue, green), assembly language, error messages and MAC address

Question 11

What are the numbers for a hex table?

Answer 11

0 = 0
1 = 1
2 = 2
3 = 3
4 = 4
5 = 5
6 = 6
7 = 7
8 = 8 
9 = 9
10 = A
11 = B
12 = C
13 = D
14 = E
15 = F

Question 12

What are images made up of?

Answer 12

Dots aka pixels

Question 13

Why is an image called a bitmap?

Answer 13

Because it’s a map of bits (pixels)

Question 14

What does PPI stand for?

Answer 14

Pixels per inch

Question 15

What does DPI stand for?

Answer 15

Dots per inch

Question 16

How many colours can you have for 1 bit, 2 bits, 3 bits, 8 bits and 16 bits?

Answer 16

1 bit = 2 colours
2 bits = 4 colours
3 bits = 8 colours
8 bits = 256 colours
16 bits = 65,536 colours

Question 17

What is meta data?

Answer 17

Image data that allows the computer to recreate the image from the binary data in the file

Question 18

What must meta data contain?

Answer 18

Height and width in pixels, colour depth in BPP(bits per pixel)

Question 19

What is analogue?

Answer 19

Made from a variation of dynamics and frequencies and records continuously

Question 20

What is sample rate?

Answer 20

The number of audio samples captured every second

Question 21

What is bit depth?

Answer 21

The number of bits available

Question 22

What is bit rate?

Answer 22

The number of bits used per second/kilobytes per second

Question 23

What is audio stored in?

Answer 23

Binary

Question 24

Why isn’t computer recorded sound pure?

Answer 24

The sound has been digitized

Question 25

What does sampling do?

Answer 25

Records snippets of sound at set intervals

Question 26

What happens to sound when recorded with a higher bit rate?

Answer 26

It will record more detail of the sound and improve the quality, will need larger storage

Question 27

What does MP3 lossy compression do?

Answer 27

It removes part of the sound that are least likely to be noticed by the human ear (e.g. frequencies we cant hear)

Question 28

Why are WAV files bigger than MP3 files?

Answer 28

WAV doesn’t use lossy compression, and are less good for sharing, but are higher quality