Waves and the Electromagnetic Spectrum

Question 1

What is wavelength?

Answer 1

The length of a full cycle.

Question 2

What is frequency?

Answer 2

The number of waves produced by a source per second.

Question 3

How do transverse waves transfer energy?

Answer 3

The vibrations are perpendicular to the direction of energy transfer of the waves.

Question 4

How do longitudinal waves transfer energy?

Answer 4

The vibrations are parallel to the direction of the energy transfer of the waves.

Question 5

What are examples of transverse waves?

Answer 5

1. Light (and EM waves)
2. Ripples on water
3. Waves on strings

Question 6

What are examples of longitudinal waves?

Answer 6

1. Sound waves

2. Shock waves (seismic)

Question 7

What are rarefactions?

Answer 7

The parts of waves where particles are spread out.

Question 8

What is the wave speed equation?

Answer 8

Speed = Frequency x Wavelength

m/s = Hz x m

Question 9

What is the law of reflection?

Answer 9

Angle of Incidence = Angle of Reflection

Question 10

What are the rules for plane mirror ray diagrams?

Answer 10

1. Same size
2. Same distance from mirror
3. Upright

Question 11

What is diffraction?

Answer 11

The spreading out of waves as they pass through a gap or obstacle.

Question 12

How big does a gap need to be for maximum diffraction?

Answer 12

The same size as the wavelength.

Question 13

What is refraction?

Answer 13

The changing of a speed of a wave as it crosses the boundary between two media, causing a change in direction.

Question 14

As waves slow down, do they bend towards or away from the normal?

Answer 14

Towards the normal.

Question 15

As waves speed up, do they bend towards or away from the normal?

Answer 15

Away from the normal.

Question 16

What are the parts of the EM spectrum?

Answer 16

Gamma
X-rays 
Utraviolet 
Light 
Infrared 
Microwaves 
Radio waves

Question 17

What useful property do long-wave radio waves have?

Answer 17

They can diffract around hills and into tunnels etc.

Question 18

Why can short-wave radio signals be received at long distances from the transmitter?

Answer 18

They are reflected off the ionosphere.

Question 19

What are microwaves used for?

Answer 19

1. Satellite communication

2. Mobile phones.

Question 20

Why are microwaves used for satellite communication?

Answer 20

They can pass through the atmosphere.

Question 21

Why could microwaves be bad for you?

Answer 21

They could heat up and damage cells in your body.

Question 22

What are infrared waves used for?

Answer 22

1. Remote controls

2. Optical fibres

Question 23

What is visible light used for?

Answer 23

Photography.

Question 24

What does the lens aperture on a camera control?

Answer 24

How much light enters the camera.