Wave Mechanics Question 80

Question: The velocity of sound is vs in air. If the density of air is increased to 4 times, then the new velocity of sound will be

[BHU 2003]

Options:

A) $ \frac{v _{s}}{2} $

B) $ \frac{v _{s}}{12} $

C) $ 12v _{s} $

D) $ \frac{3}{2}v _{s}^{2} $

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Answer:

Correct Answer: A

Solution:

$ v _{sound}\propto \frac{1}{\sqrt{\rho }}\Rightarrow \frac{v _{1}}{v _{2}}=\sqrt{\frac{{\rho _{2}}}{{\rho _{1}}}}=\sqrt{\frac{4}{1}}=2 $
$ \Rightarrow $ $ v _{2}=\frac{v _{1}}{2}=\frac{v _{s}}{2} $