Light

How are Electromagnetic waves different from Mechanical waves?

• EM waves have very short wavelengths

• EM waves transmit energy instead of matter

• EM waves can travel through the vacuum of space (without particles)

• EM waves can change direction by reflection

We use the symbol c to

• represent the frequency of light.

• represent the wavelength of light.

• represent the speed of light.

The law of reflection states that

• the angle of reflection is equal to the angle of incidence

• the angle of reflection is greater than the angle of incidence

• the image is laterally inverted

• the image must be upright and the same size as the object

A ray of light hits a plane mirror. Using the diagram determine the angle of reflection.

Mathematical Equivalence

ON

What would you call this?

• Reflection

• Diffraction

• Refraction

• Friction

The refractive index of a medium is the ratio of the speed of light in a vacuum to the speed of light in that medium 

• True

• False

Refraction occurs due to _____________

• the change in the wave's speed when it enters a new medium

• the wave bouncing off a boundary

• the change in the wave's frequency when it enters a new medium

• the wave bending around a barrier

Light has the lowest velocity in which medium?

flint glass n=1.70

air n=1.0001

water n=1.33

diamond n=2.45

• diamond

• water

• flint glass

• air

In comparison to air, glass has ​ (a)   index of refraction.

• the same
• a higher
• a lower
• an unknown

A student placed a pencil in a cup of water. The pencil appears broken because light-

• light travelling from water to air bends away from the normal making the pencil under water look closer to the surface

• light travelling from water to air bends towards the normal making the pencil under water look further away

• light travelling from air to water bends towards the normal making the pencil under water look higher up

• light travelling from air to water bends away from the normal making the pencil under water look closer to the surface