Refraction

Question 1

What happens when a wave crosses a boundary between two materials?

Answer 1

It changes speed

Question 2

What happens when a wave travels along the normal?

Answer 2

It will change speed but is not refracted

Question 3

What is refraction?

Answer 3

Refraction is the change in direction of a wave passing from one medium to another caused by its change in speed.

Question 4

What will happen to the wave if it slows down?

Answer 4

It bends towards the normal

Question 5

What will happen to the wave if it speeds up?

Answer 5

It bends away from the normal

Question 6

What is the optical density of a material?

Answer 6

How quickly light can travel through it-the higher the optical density, the slower light travels through it

Question 7

Does the frequency of a wave change when it’s refracted?

Answer 7

No

Question 8

Does the wavelength of a wave change when it’s refracted?

Answer 8

yes

Question 9

How do we showthe path of a wave?

Answer 9

Ray diagrams

Question 10

What are rays?

Answer 10

Straight lines that are perpendicular to wave fronts. They show the direction a wave is travelling in.

Question 11

How do we draw ray diagrams?

Answer 11

Question 12

What is a wave front?

Answer 12

A line showing all of the points on a wave that are in the same position as each other after a given number of wavelengths.

Question 13

What happens when a wave crosses a boundary into a denser material?

Answer 13

It travels more slowly than the rest of the wave front.

Question 14

What happens when a wave crosses a boundary at an angle?

Answer 14

• Only part of the wave will cross at first
• If it travels into a denser material, it will slow down
• By the time the while wave crosses the boundary, the faster part of the wave front will have travelled further than the slower part of the wave front
• The differences in distance travelled causes the wave to refract (bend).