NEET 2020 · PhysicsMean KEPrevious Year Question
The average thermal energy for a mono-atomic gas is: (k_B is the Boltzmann constant and T the absolute temperature)
Answer: (D) (3/2) k_B T. Correct Answer (D): (3/2) k_B T By the law of equipartition of energy, each active degree of freedom contributes ½ k_BT of average energy per molecule.
- A.(5/2) k_B T
- B.(7/2) k_B T
- C.½ k_B T
- D.(3/2) k_B T✓
Correct Answer
(D) (3/2) k_B T
Solution & Explanation
Correct Answer (D): (3/2) k_B T By the law of equipartition of energy, each active degree of freedom contributes ½ k_BT of average energy per molecule. A monatomic gas has only 3 translational degrees of freedom (f = 3), so its average thermal energy per molecule is (3/2) k_BT.
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