Wave Mechanics Question 639

Question: Velocity of sound waves in air is 330 m/s. For a particular sound wave in air, a path difference of 40 cm is equivalent to phase difference of 1.671. The frequency of this wave is

Options:

A) $ 165Hz $

B) $ 150Hz $

C) $ 60{}^\circ $

D) $ 330,Hz $

Show Answer

Answer:

Correct Answer: C

Solution:

[c] From $ \Delta x=\frac{\lambda }{2\pi }\Delta \phi , $

$ \lambda =2\pi \frac{\Delta x}{\Delta \phi }=\frac{2\pi (0.4)}{1.6\pi }=0.5 $

$ v=\frac{v}{\lambda }=\frac{330}{0.5}=660,Hz $