Question

1.A beam of light enters water at an angle of 60 degrees relative to the normal of the water surface . Find the angle of refraction?

2.Light passes from air into water . If the angle of refraction is 20° ,what is the index of refraction of the plastic?

Answer 1

1.

$\beta=\arcsin\frac{\sin\alpha}n=40.5°.$

2.

$n=\frac 1{\sin\beta}=2.9.$