1. Index of Refraction and Speed of Light
Physics Chapter 18 C

3. Index of Refraction
Index of refraction is a measure of amount of refraction
Depends on medium (optical density)
Equation for index of refraction
ns = C vs
n can be calculated for a substance by allowing a ray of light to fall on the substance
n = sin i / sin r

4. Example
Index of refraction of water is Calculate the speed of light in water.
What we know:
C = 3 x 108 m/s
n = 1.33
Equation:
n = C/v
V = C/n
Substitute:
V = (3 x 108 m/s)/(1.33)
Solve:
V = x 108 m/s
Check your answer!