Wave behaviour

Question 1

What are electromagnetic waves composed of?

Answer 1

An electric field and a magnetic field at right angles to one another.

Question 2

What is the behaviour of electromagnetic waves?

Answer 2

Electromagnetic waves may be:

1) Reflected off a surface.
2) Refracted when they move from one material to another.
3) Transmitted when they pass through a material.
4) Absorbed by different materials. For example, UV is absorbed by the skin but not by the Earth’s atmosphere.

Question 3

Explain why it is not possible to get a suntan if you are inside a house, but it is possible to listen to the radio.

Answer 3

The ultraviolet rays that cause suntans are not transmitted by the walls of houses, they are absorbed by them. Radio waves are transmitted by the walls of houses so can be detected by a radio receiver inside the house.

Question 4

Explain why we do not need a communication satellite to relay some radio waves.

Answer 4

They are refracted by the ionosphere and reflected back to receivers on the surface of the Earth.