Practice!

Sample Problem

What is the critical angle of light traveling from diamond into water? Diamond has a refractive index of 2.4, and water has a refractive index of 1.3.

Solution

We will use the formula θc = sin-1 (n2/n1) . We plug in all of the values we know,

and get θc = sin-11.3/2.4 = 33°.