Concepts Of Physics MCQ Edition [Volume 2]PhysicsKinetic Theory of Gases
For a gas at absolute temperature T , the mean square speed of its molecules is proportional to
Options
- A1 T
- BT
- CT
- DT^2
Correct answer
B. T
Step-by-step solution
The mean square speed of gas molecules is given by the square of the root mean square speed. The root mean square speed is v_ rms = 3RT M Squaring both sides, the mean square speed is v_ rms ^2 = 3RT M Alternatively, from the kinetic theory of gases, the average translational kinetic energy of a molecule is 1 2 m v^2 = 3 2 k_B T This gives v^2 = 3 k_B T m Therefore, the mean square speed is directly proportional to the absolute temperature T .