In an adiabatic expansion process, the density of an ideal gas changes from $\rho_1$ to $\rho_2$ such that $\rho_2 / \rho_1=\alpha$. Select the correct statement(s) about this process.

• A

  The corresponding change in temperature is given by $T_2 / T_1=\alpha^{1-\gamma}$.
• Correct answer
  B

  The corresponding change in the speed of sound is given by $C_2 / C_1=$ $\alpha^{(\gamma-1) / 2}$.
• Correct answer
  C

  The corresponding change in averaged collision frequency is given by $\nu_2 / \nu_1=$ $\alpha^{(\gamma+1) / 2}$.
• Correct answer
  D

  The corresponding change in mean free path is given by $\lambda_2 / \lambda_1=\alpha^{-1}$.

Hence, the correct answer is options: 'B', 'C', 'D'.