COMEDK2021PhysicsKinetic Theory of Gases
The average energy associated with a monoatomic molecule is
Options
- AK_ B T
- B1 2 K_ B T
- C3 2 K_ B T
- D2 K_ B T
Correct answer
C. 3 2 K_ B T
Step-by-step solution
A monoatomic gas molecule has 3 degrees of freedom ( f = 3 ) corresponding to its translational motion along the x , y , and z axes. According to the law of equipartition of energy, each degree of freedom contributes 1 2 K_ B T to the average kinetic energy of the molecule. Therefore, the total average energy E is given by E = f 1 2 K_ B T = 3 1 2 K_ B T = 3 2 K_ B T . Answer: 3 2 K_ B T