P13. Electromagnetic Waves

Question 1

What type of spectrum do electromagnetic waves form?

Answer 1

A continuous spectrum

Question 2

Order the types of electromagnetic radiation from lowest to highest frequency

Answer 2

Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays

Question 3

How do the speeds of EM radiation differ in a vacuum and in air?

Answer 3

Electromagnetic waves all travel at the same speed in a vacuum and in air

Question 4

What property of waves in different mediums causes refraction?

Answer 4

Velocity
Wave speed is slower in denser materials, causing refraction

Question 5

In which direction (relative to the normal) do waves refract when entering a denser medium?

Answer 5

They bend towards the normal
The angle of refraction is less than the angle of incidence

Question 6

What type of waves can be produced by oscillations in an electrical circuit?

Answer 6

Radio waves

Question 7

How can radio waves create an alternating current in a circuit?

Answer 7

When radio waves are absorbed, they can induce oscillations in a circuit with the same frequency as the waves themselves.

Question 8

Where do gamma rays originate from?

Answer 8

They originate from changes in the nuclei of atoms

Question 9

What health effects can ultraviolet waves cause?

Answer 9

They can cause the skin to age prematurely
They can increase the risk of developing skin cancer

Question 10

What health effects can X-rays and Gamma rays cause?

Answer 10

They are ionising radiation so can cause mutations in genes
They can lead to increased risk of developing various cancers

Question 11

Give three practical uses for infrared radiation

Answer 11

1. Electrical heaters
2. Cooking food
3. Infrared cameras

Question 12

Give two practical uses for microwave radiation?

Answer 12

1. Satellite communications
2. Cooking food

Question 13

Give two practical uses for radio waves.

Answer 13

1. Television transmission
2. Radio transmission