angle physics question, please help :)

Question

Light traveling from a transparent material with index of refraction 1.25 strikes a surface with an angle 72 degrees relative to a normal line from that surface. When the light enters the second material, with an index of refraction 1.44, what angle with the ray form with the normal? 
in terms of degrees. Do not include units in your answer.
to a precision of 0.2 degrees. 

Answer 1

Use Snell's Law.

 

We have:

 

n₁ = 1.25

 

n₂ = 1.44

 

θ₁ = 72°

 

We need θ₂.

 

n₁ sin θ₁ = n₂ sin θ₂.

 

1.25 sin 72° = 1.44 sin θ₂.

 

θ₂ = sin^-1 ((1.25/1.44) sin 72°) = 55.6°