A ray of light strikes a water-glass interface at an angle of incidence of 35º. The angle of refraction is
A) 40.3º.
B) 22.1º.
C) 30.6º.
D) 59.4º.
E) 19.7º.

Question

A ray of light strikes a water-glass interface at an angle of incidence of 35º. The angle of refraction is
A) 40.3º. 
B) 22.1º. 
C) 30.6º. 
D) 59.4º. 
E) 19.7º.

Quizplus · Accepted Answer

Using Snell's Law: 
n1 sin(theta1) = n2 sin(theta2) 
Assuming n1 = 1 (air) and n2 = 1.33 (water), and theta1 = 35º: 
1.00 x sin(35º) = 1.33 x sin(theta2) 
sin(theta2) = 0.4494 
theta2 = sin^-1(0.4494) = 30.6º, which is answer choice C.

A Ray of Light Strikes a Water-Glass Interface at an Angle