Question

Consider a gas with molar mass M.If the sound at frequency f is introduced to a tube of this gas at temperature T then an internal acoustic standing wave is set up with nodes separated by L.The adiabatic constant (gamma=Cp/ Cv is

Ans:(4Mf

Answer 1

$v=2Lf,$

also $v=\sqrt{\frac{\gamma RT}M},$ $\implies$

$4L^2f^2=\frac{\gamma RT}M,$

$\gamma=\frac{4Mf^2L^2}{RT}.$