Section 2

Question 1

What is a bit?

Answer 1

A binary digit - a single 1 or 0

Question 2

What is a byte?

Answer 2

A group of 8 bits

Question 3

What is a nibble?

Answer 3

4 bits (half a byte)

Question 4

How many bytes are in 1 kilobyte (kB)?

Answer 4

10³ bytes

Question 5

How many bytes are in 1 gigabyte (GB)?

Answer 5

10⁹ bytes

Question 6

How many bytes are in 1 terabyte (TB)?

Answer 6

10¹² bytes

Question 7

How many bytes are in 1 petabyte (PB)?

Answer 7

10¹⁵ bytes

Question 8

What is the denary value of binary 10110?

Answer 8

22

Question 9

What is the denary value of binary 11111111?

Answer 9

255

Question 10

How to convert from denary to binary?

Answer 10

Find the highest column heading which can be taken out of the number, and continue

Question 11

Convert denary 128 to binary

Answer 11

10000000

Question 12

What happens when adding 1 + 1 in binary?

Answer 12

10 (0 in that column, 1 passed to next)

Question 13

What is an overflow error?

Answer 13

When a calculation results in a number too large to be stored in the allocated number of bits

Question 14

What happens when you shift a binary number left by 1 place?

Answer 14

The number is multiplied by 2

Question 15

What happens when you shift a binary number right by 1 place?

Answer 15

The number is divided by 2

Question 16

What is hexadecimal?

Answer 16

A base 16 number system using digits 0-9 and letters A-F

Question 17

What does A represent in hexadecimal?

Answer 17

10 in denary

Question 18

Why is hexadecimal used in computing?

Answer 18

It’s easier for humans to read and remember than long binary strings; each hex digit represents 4 bits

Question 19

What is ASCII?

Answer 19

American Standard Code for Information Interchange - a character encoding standard

Question 20

How many bits does standard ASCII use per character?

Answer 20

7 bits

Question 21

How many characters can 7-bit ASCII represent?

Answer 21

128 characters (2⁷)

Question 22

How many bits does extended ASCII use?

Answer 22

8 bits per character

Question 23

How many characters can extended ASCII represent?

Answer 23

256 characters (2⁸)

Question 24

Are ASCII codes for uppercase and lowercase letters the same?

Answer 24

No - lowercase letters have higher ASCII values than uppercase

Question 25

What is Unicode?

Answer 25

A universal character encoding standard that can represent characters from all world languages

Question 26

How many bits does 16-bit Unicode use per character?

Answer 26

16 bits

Question 27

How many characters can 16-bit Unicode represent?

Answer 27

65

Question 28

What is a pixel?

Answer 28

A picture element - the smallest single point in a digital image

Question 29

What is image resolution?

Answer 29

The number of pixels that make up an image

Question 30

What is colour depth?

Answer 30

The number of bits used to represent the colour of each pixel

Question 31

How many colours can be represented with 1 bit colour depth?

Answer 31

2 colours (2¹)

Question 32

How many colours can be represented with 8 bit colour depth?

Answer 32

256 colours (2⁸)

Question 33

What is the formula for calculating image file size?

Answer 33

(Width × Height × Colour Depth) ÷ 8 bytes

Question 34

What is metadata?

Answer 34

Data about data - information stored about a file such as creation date

Question 35

What could metadata include?

Answer 35

- File type - Time and date of creation - Creator or author of data - File Size

Question 36

What is an Analogue-to-Digital Converter (ADC)?

Answer 36

A device that converts analogue signals (like sound waves) into digital format

Question 37

What is sample rate?

Answer 37

The number of times per second that the amplitude of a sound wave is measured

Question 38

What is sample resolution?

Answer 38

The number of bits used to store each audio sample

Question 39

What is 1 Hertz (Hz)?

Answer 39

1 sample per second

Question 40

What is the formula for calculating sound file size?

Answer 40

(Sample Rate × Sample Resolution × Duration in seconds) ÷ 8 bytes

Question 41

How does increasing sample rate affect sound quality?

Answer 41

Higher sample rate = better quality playback (more accurate representation of the sound wave)

Question 42

How does increasing sample resolution affect sound quality?

Answer 42

Higher resolution = better accuracy (more precise amplitude measurements)

Question 43

What is compression?

Answer 43

Reducing the size of a file to save storage space or reduce transmission time

Question 44

What is lossy compression?

Answer 44

Compression that permanently removes some data from the file

Question 45

What is lossless compression?

Answer 45

Compression where no data is lost and the original file can be perfectly reconstructed

Question 46

Give examples of lossy compression

Answer 46

JPEG (.jpg) - Photos Windows Media Player (.wmv) - Window Media Compression MP3 (.mp3) - Audio Files MPEG-1 & MPEG-2 (.mpg/.mp2) - Video Files (low -resolution on CD/ high-resolution on DVD)

Question 47

Give examples of lossless compression?

Answer 47

ZIP (.zip) - Any files or folders of files Portable Network Graphic (.png) Graphic Interchange Format (.gif) - Good for images with large areas for colour, ideal for web graphics

Question 48

Why would you use lossy compression?

Answer 48

To achieve smaller file sizes when some loss of quality is acceptable (photos

Question 49

Why would you use lossless compression?

Answer 49

When all original data must be preserved (text files

Question 50

What are the benefits of file compression?

Answer 50

Reduced storage space needed; faster transmission over networks; allows large files to be sent as email attachments

Question 51

What is the difference between PPI and DPI?

Answer 51

PPI (pixels per inch) measures screen resolution; DPI (dots per inch) measures print resolution

Question 52

What is the largest number that can be stored in 8 bits?

Answer 52

255 (11111111 in binary)

Question 53

What is a bitmap image?

Answer 53

An image made up of individual pixels

Question 54

What is a vector graphic?

Answer 54

An image made up of lines and shapes with specific properties (not made of pixels)

Question 55

Why can't you calculate with numbers input as strings?

Answer 55

Because the ASCII code for a digit character (e.g. '5') is different from the pure binary value for that number

Question 56

What would metadata about a digital image include?

Answer 56

- Dimensions of the Image - Image Resolution - Colour Depth

Question 57

How many bytes are in 1 megabyte (MB)?

Answer 57

10⁶ bytes