Question

Light travels through air at 300 million ms⁻¹. On entering water it slows down to 225 million ms⁻¹. Calculate the refractive index of water.

Answer 1

Here, mediums 1 and 2 are air and water, respectively.
Now,
Refractive index of water = Speed of light in air / Speed of light in water
= 300 million ms^−1  / 225 million ms^{−1 
=  1.33
Therefore, refractive index of water is 1.33.}