Chapter 1: Data representation

Question 1

Define a bit

Answer 1

The basic computing element that is either 0 or 1

Question 2

Define the binary number system

Answer 2

A number system based on 2 and can only use values 0 and 1

Question 3

Define an error code

Answer 3

It is an error message generated by the computer

Question 4

Define a MAC address

Answer 4

It is an address (given in hexadecimal) that uniquely identifies a device on the internet in the form of NN-NN-NN-DD-DD-DD

(NN-NN-NN is the manufacturer code)

(DD-DD-DD is the device code)

Question 5

Define an IP address

Answer 5

It is an address that uniquely identifies each device connected to a network identifying their location.

Question 6

Define HTML

Answer 6

It is used to design and write webpages

Question 7

Define an overflow error

Answer 7

The result of doing a calculation that produces a value that is too big for the computers allocated word size

Question 8

Define logical shift

Answer 8

An operation that shifts bits to the left or right in a register.

(Any bits shifted out of the register are replaced with zeroes)

Question 9

Define the two’s complement

Answer 9

A method of representing of negative numbers in binary

(When applied to an 8-bit system, the left most bit is given the value -128

Question 10

What is an ASCII code

Answer 10

A character set for all the characters on a standard keyboard and control codes.

Question 11

Define a character set

Answer 11

a list of characters that have been defined by computer hardware and software.

Question 12

Define an Unicode

Answer 12

a character set which represents all the languages of the world

Question 13

Define a sampling resolution

Answer 13

the number of bits used to represent sound amplitude in digital sound recording

Question 14

Define what is bit depth

Answer 14

the number of bits used to represent the smallest unit in a sound file

Question 15

Define what is color depth

Answer 15

the number of bits used to represent the colours of a pixel

Question 16

Define sampling rate

Answer 16

the number of sound samples taken per second in digital sound recording

Question 17

Define bitmap image

Answer 17

an image made up of pixels

Question 18

Define pixel

Answer 18

the smallest element used to make up an image on a display

Question 19

Define image resolution

Answer 19

the number of pixels in the X–Y direction of an image,

Question 20

Define pixelated image

Answer 20

this is the result of zooming into a bitmap image; on zooming out the pixel density can be diminished to such a degree that the actual pixels themselves can be seen

Question 21

Define pixel density

Answer 21

number of pixels per square inch

Question 22

Define compression

Answer 22

reduction of the size of a file by removing repeated or redundant pieces of data;

Question 23

Define bandwidth

Answer 23

the maximum rate of transfer of data across a network, measured in kilobits per second (kbps) or megabits per second (Mbps)

Question 24

Define lossy file compression

Answer 24

a file compression method in which parts of the original file cannot be recovered during the decompression process

Question 25

Define lossless file compression

Answer 25

A file compression method that allows the original file to be fully restored during the decompression process, for example, run length encoding (RLE)

Question 26

Define audio compression

Answer 26

a method used to reduce the size of a sound file using perceptual music shaping

Question 27

Define MP3

Answer 27

a lossy file compression method used for music files

Question 28

Define MP4

Answer 28

a lossy file compression method used for multimedia files

Question 29

Define JPEG

Answer 29

; a form of lossy file compression used with image files which relies on the inability of the human eye to distinguish certain colour changes and hues

Question 30

Define RLE

Answer 30

a lossless file compression technique used to reduce the size of text and photo files in particular

Question 31

How do you calculate The file size of an image

Answer 31

image resolution (in pixels) × colour depth (in bits)

Question 32

How do you calculate The size of a mono sound file

Answer 32

sample rate (in Hz) × sample resolution (in bits) × length of sample (in seconds)

Question 33

Why is file compression necessary

Answer 33

» to save storage space on devices such as the hard disk drive/solid state drive

» to reduce the time taken to stream a music or video file

» to reduce the time taken to upload, download or transfer a file across a network

» the download/upload process uses up network bandwidth

» reduced file size also reduces costs.

Question 34

Define a data packet

Answer 34

a small part of a message/data that is transmitted over a network

Question 35

Define a data packet

Answer 35

a small part of a message/data that is transmitted over a network