Unit 01 - Information Representation

Question 1

Hexadecimal

Answer 1

A number system that uses 16 distinct symbols (the numbers 0-9 and the letters A-F) to represent a number. Also called hex or base-16.

Question 2

Denary

Answer 2

Decimal numbers written with the symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

Question 3

Bit

Answer 3

A digit in the binary number system written using either of the symbols 0 and 1. Bit is short for binary digit.

Question 4

Byte

Answer 4

A group of eight bits treated as a single unit. 0000 0000

Question 5

Nibble

Answer 5

A group of four bits 0000

Question 6

Decimal prefix

Answer 6

A prefix to define the magnitude of a value. Examples are kilo, mega, giga and tera. They represent factors of 10^3, 10^6, 10^9 and 10^12 respectively.

Question 7

Binary prefix

Answer 7

A prefix to define the magnitude of a value. Examples are kibi, mebi, gibi and tebi. They represent factors of 2^3, 2^6, 2^9 and 2^12 respectively.

Question 8

One’s Complement

Answer 8

The binary number obtained by subtracting each digit in a binary number from 1.

Question 9

Two’s Complement

Answer 9

A method of representing signed (i.e. negative and positive) numbers where the most significant bit has a negative place value.

Question 10

Overflow

Answer 10

A condition when the result of a calculation is too large to fit into the number of bits defined for storage.

Question 11

Binary coded decimal (BCD)

Answer 11

Storage of a binary value representing one denary digit in a nibble (4 bits)

Question 12

Packed BCD

Answer 12

When two BCD (binary coded decimal) nibbles are stored in one byte

Question 13

ASCII

Answer 13

American Standard Code for Information Interchange. An encoding format that allocates a numeric code to characters (e.g. digits, letters, punctuation marks, etc.) in order for them to be represented in binary within a computer system

Question 14

Unicode

Answer 14

An encoding format that allocates a numeric code to characters in order for them to be represented in binary within a computer. Unicode covers the characters for the most known alphabets and special symbols (e.g. mathematical operators, geometric shapes, arrows, emojis, etc.)

Question 15

Bitmapped graphic

Answer 15

A type of digital image that is stored as pixels. Each pixel is represented by a single colour code. Also called bitmapped image.

Question 16

Colour depth

Answer 16

Also known as bit depth. The number of bits used to represent the colour of a pixel in a bitmapped graphic. Represents each of the red, green and blue colours.

Question 17

Pixel

Answer 17

Short for picture element. The smallest addressable part of a bitmap image that corresponds to a single colour

Question 18

Image resolution

Answer 18

The number of pixels in the bitmap file defined as the product of the width and height values

Question 19

Screen resolution

Answer 19

The product of the width and height values for the number of pixels that the screen can display

Question 20

Vector Graphic

Answer 20

An image that is stored as a set of instructions to recreate it. Uses a drawing list made up of a set of objects and their properties.

Question 21

Drawing Object

Answer 21

A component defined by geometric formulae and associated properties

Question 22

Drawing list

Answer 22

Contains one set of values for each drawing object

Question 23

Property

Answer 23

Defines one aspect of the appearance of the drawing object

Question 24

Metadata

Answer 24

Data about data. Data that provides information about other data.

Question 25

File Header

Answer 25

A set of bytes at the beginning of a bitmap file which identifies the file and contains information about the coding used.

Question 26

Analogue Data

Answer 26

Data obtained by measurement of a physical property which can have any value from a continuous range of values. For instance sound made by the human voice.

Question 27

Digital Data

Answer 27

Data that has been stored as a binary value which can have one of a discrete range of values.

Question 28

Sample Resolution

Answer 28

The number of bits used to encode each sample. Determines how accurately the sample can be represented. Also called bit depth.

Question 29

Sampling Rate

Answer 29

The number of samples captured per second. Expressed in hertz (where 1Hz is 1 sample per second)

Question 30

Sampling

Answer 30

A method of capturing analogue data sot that it can be converted to digital form, for example, by measuring sound at fixed intervals

Question 31

Sampling interval

Answer 31

The amount of time (measured in seconds) between two consecutive samples.

Question 32

Bit pattern

Answer 32

A unique string of binary digits used in a representation.

Question 33

Compression

Answer 33

The process of reducing file size by applying a compression algorithm

Question 34

Lossy Compression

Answer 34

A method where data is permanently lost during the compression process and must be approximated when the file is decompressed

Question 35

Lossless compression

Answer 35

Coding techniques that allow subsequent decoding to recreate exactly the original file

Question 36

Encoding

Answer 36

The process of representing data in binary form

Question 37

Dictionary-based method

Answer 37

A lossless method of compression where each different word or group of characters is assigned a code. When the file is compressed, the words or character groups are substituted by the codes.

Question 38

RLE

Answer 38

Run Length Encoding. A lossless compression method where repeated runs of binary data are represented by a single instance of the data and the number of repetitions.