Kinetic Theory Of Gases Question 36

Question: A nitrogen molecule has some rms speed at $ 0{}^\circ C $ on the surface of the earth. With this speed, it goes straight up. If there is no collisions with other molecules, the molecule will rise up to a height of

Options:

A) 82 km

B) 12.4 km

C) 10.6 km

D) 152 km

Show Answer

Answer:

Correct Answer: B

Solution:

[b] $ v _{rms}=\sqrt{\frac{3RT}{M}}=\sqrt{\frac{3\times 8.31\times 273}{28\times {{10}^{-3}}}}=493m/s $ Thus $ \frac{1}{2}mv _{rms}^{2}=\frac{mgh}{1+\frac{h}{R}}. $ After substituting the values and simplifying, we get h= 12.4 km