Wave Mechanics Basics Of Mechanical Waves Question 92

Question: A wave has velocity u in medium P and velocity 2u in medium Q. If the wave is incident in medium P at an angle of 30° then the angle of refraction will be

[J & K CET 2005]

Options:

A) 30°

B) 45°

C) 60°

D) 90°

Show Answer

Answer:

Correct Answer: D

Solution:

$ v=\frac{\sin i}{\sin r}=\frac{v _{1}}{v _{2}} $

Therefore $ \sin r=\sin 30{}^\circ \times \frac{2u}{u}\Rightarrow \sin r=\frac{1}{2}\times 2\times 1 $
$ \Rightarrow r=90{}^\circ $