A light wave moves from diamond (n = 2.1) into water (n = 1.83) at an angle of 19°. What angle does it have in water?

  θ  = 0.3736

Explanation:

For this exercise, how light passes through two media separated by a distance, so its movement is governed by the law of refraction.

            n₁ sin  19 = n₂  sint  θ

let's use subscript 1 for diamond and sub start 2 for water

            sin θo = n₁ / n₂ sin θ

            sin θ  = sin 19  0.325                                                                                                                                                                                                                                                                              56

            θ  = 0.3736

the answer to this question is 60 n