Question

Relation between critical angle of water C_w and that of the glass C_g is ________ . (given, n_w = (4/3), n_g = 1.5)

(A) C_w < C_g

(B) C_w = C_g

(C) C_w > C_g

(D) C_w = C_g = O

Answer 1

The correct option is (C) C_w > C_g.

Explanation:

sin c = (1 / η)

 c = sin^–1(1 / η)

Hence  Critical angle for water = C_w = sin^–1{1 / (4/3)} = sin^–1(3/4) = 48.6°

Critical angle for glass = C_g = sin^–1(1 / 1.5) = 41.8

hence C_w > C_g.