Question

Which of the following expression is not correct for rms velocity?

• A. $\sqrt{\frac{3\rho }{P}}$
• B. $\sqrt{\frac{3RT}{M}}$
• C. $\sqrt{\frac{3PV}{M}}$
• D. $\sqrt{\frac{2E_k}{M}}$

Answer 1

The correct option is A $\sqrt{\frac{3\rho }{P}}$

$V_{rms}=\sqrt{\frac{3PV}{M}}=\sqrt{\frac{3RT}{M}}$

Kinetic enegry of the gas $E_K=\frac{1}{2}\times M{V}_{rms}^2$

$\therefore V_{rms}=\sqrt{\frac{2E_K}{M}}$

$\therefore$ option A is incorrect