Question

2) The velocity of sound is proportional to the square root
of molecular weight of the medium.
a) inversely b) directly
c) doubble d) half​

Answer 1

The velocity of sound is INVERSELY proportional to the square root of molecular weight of the medium.

As per Newton's Laws of Speed of Sound in gas, the propagation of sound through a medium is an isothermal process and the velocity can be expressed as:

$\boxed{ \rm v = \sqrt{\dfrac{ RT}{m}} }$

However, Laplace made a correction that:

• Propagation of sound through a media is an adiabatic process and hence there is no time for heat exchange with the surroundings.

$\implies \rm v = \sqrt{\dfrac{ \gamma RT}{m}}$

$\boxed{ \implies \rm v \propto \sqrt{\dfrac{1}{m}}}$

Hope It Helps.