Question

The temperature of an ideal gas is increased from 140 K to 560 K. If at 140 K the Root Mean Square velocity of the gas molecules is u, at 560 K it becomes:

• A. 5u
• B. 2u
• C. u/2
• D. u/4

Answer 1

The correct option is B 2u

The root mean square velocity is directly proportional to the square root of temperature.
Thus when the temperature increases from 140 K to 560 K, the root mean square velocity increases from u to $\sqrt{\frac{560}{140}}u=2u$.