Images and Sound

Question 1

What does PIXEL stand for?

Answer 1

Picture Element

PIXEL is short for ‘picture element’, the smallest unit of a digital image.

Question 2

What is the typical resolution of a 13-inch monitor?

Answer 2

640 pixels horizontally and 480 pixels vertically

Question 3

What are the primary colors used in the RGB model?

Answer 3

Red, Green, Blue

Question 4

What is the term for the amount of memory dedicated to each screen pixel?

Answer 4

Colour depth

Question 5

How many colors can a 1-bit display system manage?

Answer 5

2 colors (black or white)

Question 6

How many unique colors can an 8-bit display show?

Answer 6

256 colors

Question 7

What is a True-colour or 24-bit display capable of showing?

Answer 7

Millions of unique colors

Question 8

What is the formula for calculating the total number of colors in a 24-bit display?

Answer 8

8 bits for red + 8 bits for green + 8 bits for blue = 24 bits

Question 9

What is the difference between bitmap and vector images?

Answer 9

Bitmap images are stored as a grid of pixels, while vector images are stored as geometrical shapes defined by specific properties

Question 10

Name two popular graphics formats for bitmap images.

Answer 10

• JPG
• GIF

Question 11

What are the advantages of vector images?

Answer 11

• Does not deteriorate when enlarged
• Uses less memory
• Easier to edit/manipulate

Question 12

What must be done to convert sound into digital form?

Answer 12

Use an analogue-to-digital converter (ADC)

Question 13

What is Pulse Code Modulation (PCM)?

Answer 13

A technique to convert an analogue signal into a digital signal by sampling at fixed intervals

Question 14

What is the Nyquist rate?

Answer 14

The sampling rate should be at least twice the maximum frequency of the sound wave to avoid loss

Question 15

What is MIDI?

Answer 15

A sequence of event messages that can synthesize musical notation

Question 16

What information is stored in a MIDI file?

Answer 16

• Length/duration of note
• Instrument
• Velocity
• Volume
• Timbre
• Pedal effects
• Channel

Question 17

What is the sampling rate required for CD quality sound?

Answer 17

44,000 samples per second (44 kHz)

Question 18

What is audio compression?

Answer 18

The process of minimizing storage space/bandwidth requirements for audio data

Question 19

Differentiate between analogue sound and digital sound.

Answer 19

Analogue sound is continuous, while digital sound is discrete and stored in binary form.

Question 20

What are the two parts of audio compression?

Answer 20

• Encoding
• Decoding

Question 21

What does a 16-bit sound card represent?

Answer 21

65,536 sound levels

Question 22

What is the significance of recording a stereo sound?

Answer 22

It doubles the number of samples needed per second

Question 23

What is the file size formula for sound?

Answer 23

Sampling Rate x BitRate x No. of seconds

Question 24

What does the term ‘quantisation’ refer to in PCM?

Answer 24

Approximating the height of each PAM pulse by an n-bit integer

Question 25

True or False: Vector images can be resized without loss of quality.

Answer 25

True

Question 26

How is the resolution of an image expressed?

Answer 26

Width x Height in pixels

Question 27

What is the significance of the term ‘sampling frequency’?

Answer 27

It must be at least twice the highest frequency in the analogue signal

Question 28

Fill in the blank: The process of measuring the value of the analogue signal at regular intervals is called _______.

Answer 28

Sampling