Material Speed of Light (m/s) Index of Refraction

Air 300,000,000 1.00
Water 225,000,000 1.33
Diamond 124,000,000 2.42
Glass ????????? 1.50

As light slows down, it bends or refracts. The index of refraction helps predict the amount of bending. How are the speed of light and the index of refraction related?
Responses

A The speed of light is a constant in all materials.The speed of light is a constant in all materials.

B The index is proportional to the speed of light in the medium.The index is proportional to the speed of light in the medium.

C The index is inversely proportional to the speed of light in the medium.The index is inversely proportional to the speed of light in the medium.

D The index is proportional to the square of the speed of light in the medium.The index is proportional to the square of the speed of light in the medium.

1 answer

The correct response is:

C The index is inversely proportional to the speed of light in the medium.

This is because the index of refraction (n) is defined as the ratio of the speed of light in vacuum (c) to the speed of light in the medium (v):

\[ n = \frac{c}{v} \]

As the speed of light in the medium decreases (lower v), the index of refraction increases (higher n), showing that they are inversely related.