An Oil Layer That Is 5

Multiple Choice

An oil layer that is 5.0 cm thick is spread smoothly and evenly over the surface of water on a windless day. What is the angle of refraction in the water for a ray of light that has an angle of incidence of 45° as it enters the oil from the air above? (The index of refraction for oil is 1.15, and for water it is 1.33.)

A) 27°
B) 32°
C) 36°
D) 39°
E) 52°