Topic 1: Digital Data

Question 1

What is data

Answer 1

Data is raw facts and figures which has not been processed and has no meaning

Question 2

What is information

Answer 2

Data that has been processed and therefore has meaning and context

Question 3

What is the difference between data and information

Answer 3

Data is raw facts and figure which has no meaning whereas information is data that has been processed and given meaning and context

Question 4

1 Bit =
1 Nibble =
1 Byte =
1 Kilobyte =
1 Megabyte =
1 Gigabyte =
1 Terabyte =

Answer 4

1 Bit = 1
1 Nibble = 4 bits
1 Byte = 8 bits
1 Kilobyte = 1024 bytes
1 Megabyte = 1024 kilobytes
1 Gigabyte = 1024 megabytes
1 Terabyte = 1024 gigabytes

Question 5

What is a pixel

Answer 5

Smallest area of a digital image that can be edited on a graphic

Question 6

Features of a pixel

Answer 6

Each pixel has its own colour
When combined pixels form an image
Each pixel is stored as a series of binary digits

Question 7

What is resolution

Answer 7

The measure of the quality of an image. The higher the resolution the better the quality of an image.

Question 8

What is resolution measured in

Answer 8

DPI - Dots per inch

Question 9

Disadvantages of resolution

Answer 9

High overall image loading and processing times on computers
Higher overall image file transfer times across communication links

Question 10

What are bitmap graphics

Answer 10

Bitmap graphics are made up of pixels which can provide high quality photos and millions of colours

Question 11

What is

JPEG
TIFF
GIF

Answer 11

Joint photographic expert group
Tagged image file format
Graphical interchange format

Question 12

What is a thumbnail

Answer 12

A thumbnail image is smaller version of an image. You click the thumbnail to display the full version

Question 13

Advantages of thumbnail

Answer 13

Reduces loading time
Shows a preview of the image

Question 14

What is a vector based image

Answer 14

Vector graphics are made up of mathematical equations unaffected by scaling

Question 15

Vector image features

Answer 15

Image can be resized without loss of quality
Image is made up of objects defined by equations
Objects can be edited
Image quality doesn’t depend on res
Suitable for diagrams and symbols

Question 16

Bitmap image features

Answer 16

File is made up of a grid of tiny pixels
high quality images
can edit individual pixels
When stretched the image can become blurry or pixelated

Question 17

What is streaming

Answer 17

Streaming involves initiating the playing of a video shortly after the first few seconds of the video file have downloaded, allowing the video to be watched in “real time”

Question 18

Advantages of streaming

Answer 18

Allows the user to watch the video as it downloads
Sucessive segments downloaded but not saved

Question 19

What is a buffer

Answer 19

A part of memory used to store a downloaded video before it is watched

Question 20

Computers store data in what format and convert to what

Answer 20

Computer stores data in digital format however we hear in analogue so ADC, digital to analogue conversion is necessary.

Question 21

What is an analogue signal

Answer 21

Continuous signal, that represents a physical such as sound temp or light

Question 22

What is digital signal

Answer 22

A binary signal with 1s and 0s as values

Question 23

Explain the ADC process

Answer 23

Sound input
Analogue to digital convertor
Computer can process the data
Digital to analogue converter
Sound output to speaker

Question 24

What is sound sampling

Answer 24

Regularly measuring the voltage of signals

Question 25

What is the sample rate and what is it measured in

Answer 25

The quantity of samples taken per second measured in Hz.

Question 26

What happens with the higher the sample rate

Answer 26

The better the digital representation

Question 27

Increasing sample rate does what to an audio file

Answer 27

increases the quality

Question 28

What is the bit depth

Answer 28

Number of bits allocated per sample taken

Question 29

Increasing bit depth does what to digital sound

Answer 29

increases quality of digital sound

Question 30

What is the bit rate

Answer 30

The number of bits required to store 1 second of sound

Question 31

Bit rate calculation

Answer 31

Bit depth x Sample rate = BIT Rate

Question 32

What is data portability

Answer 32

Data portability denotes data that can be directly transferred between hardware devices without having to be entered again

Question 33

What is MIDI

Answer 33

Musical Instrument Digital Interface

Question 34

What is PDF

Answer 34

Portable Document Format

Question 35

PDF files can be protected
Widely used on the internet due to its platform independence
Preserves all the fonts, formatting, graphics and colour of any source document regardless of the application and platform

Answer 35

PDF files can be protected
Widely used on the internet due to its platform independence
Preserves all the fonts, formatting, graphics and colour of any source document regardless of the application and platform

Question 36

What is Data Compression

Answer 36

The process of trying to reduce the size of a file, if a file is too big it is too slow to process, download and upload

Question 37

What are compression, decompression, and zip files

Answer 37

Compression helps reduce the file size and then decompression software increases the size of the file again.
Zip files are used to compress multiple files into single smaller sized files

Question 38

What is compression

Answer 38

Decreases the file size and removes detail not visible to the human eye from the image

Question 39

What is lossless and lossy compression

Answer 39

Lossless- The image data is stored without any loss of quality
Lossy- The data is stored by stripping out unnecessary data and reducing image quality

Question 40

Difference between lossless and lossy

Answer 40

Lossless means picture doesn’t lose any of its original quality even when compressed whereas lossy reduces the file size by removing data and reduces quality