Three Materials with N₁ < N₂ < N₃ Are Arranged

Multiple Choice

Three materials with n₁ < n₂ < n₃ are arranged in layers of uniform thickness.A light ray in air enters the first layer at an angle of incidence of 40° and the ray eventually exits the third layer at the refracted angle θ in air.What is the value of θ?

A) Some angle more than 40°.
B) Insufficient information to answer.
C) 40°.
D) Some angle less than 40°.