Topic 2 - refraction

Question 1

When light enters a MORE DENSE medium,

Answer 1

the light ray bends TOWARDS the normal

Question 2

When light enters a LESS DENSE medium the

Answer 2

light ray bends AWAY from the normal

Question 3

refractive index formular

em waves travel at …

Answer 3

All EM waves travel at c = 300,000,000 ms-1 in a vacuum

At they enter matter they slow down to a new speed v

“The refractive index, n, of a substance is the ratio of the speed of light in a vacuum to it’s speed in the substance”

n = c speed of light in a vacuum
v speed of light in the substance

Question 4

Refractive Index – Some Facts

Answer 4

Light always travels fastest in a vacuum

Value is always greater than 1

Higher index means more deflection

High value materials are ‘optically dense’

Question 5

formular for refractive index

Answer 5

Rather than using the speed of the light, we can also use the incidence and refracted angles to find ‘n’. The formula now becomes…

n = sin i / sin r

angle of incidence
angle of reflection