SP5 - light and the EM spectrum

Question 1

Where are the angles of incidence and reflection measured?

Answer 1

Between the light ray and the normal.

Question 2

What does the law of reflection state?

Answer 2

Angle of incidence = angle of reflection.

Question 3

What is specular reflection?

Answer 3

Reflection from a smooth flat surface.

Question 4

The image in a mirror is:

Answer 4

• Upright

- Virtual

Question 5

What do the rays appear like in a virtual image?

Answer 5

The rays appear to diverge from behind the mirror, so the image appears to come from behind the mirror.

Question 6

What is diffuse reflection?

Answer 6

When a ray hits a rough surface. Instead of forming an image, the reflected light is scattered in all directions. This may can a distorted image of the object, as occurs with rippling water, or no image at all. Each individual reflection still obeys the law of reflection, but the different parts of the rough surface are at different angles.

Question 7

Why might light rays change direction?

Answer 7

Because of the density of the material it’s travelling through.

Question 8

What is refraction?

Answer 8

The change in direction of a wave at a boundary.

Question 9

Glass is denser than air, so a light ray passing from air into glass…

Answer 9

Slows down.

Question 10

So a light ray passing from glass into air…

Answer 10

Bends away from the normal by the same angle.