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Question #84419
The Question
A classical dilute gas consisting of non-interacting particles, each of mass and positive charge , is maintained at an absolute temperature . The gas is confined in the half-space and is subjected to an external potential energy field given by , where and are positive constants. If is the Boltzmann constant, what is the average total energy per particle of this gas in thermal equilibrium?
Options
- A.
- B.
3 k_B T
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Intuition_Breaker
Train your brain to resist "obvious" answers that are designed to deceive your intuition.
Concepts Behind This Question
Equipartition Theorem|Maxwell-Boltzmann Distribution|Coulombic Central Force
Why This Question Is Tricky
Examiner Levers
Dimensional Analysis
Tests if the student verifies units/dimensions before selecting.
Difficulty Boost : +2Common Mistakes
This question tests the fundamental application of the Equipartition Theorem and Maxwell-Boltzmann statistics beyond memorized formulas.
Students often blindly assign (1/2)kT to every degree of freedom, incorrectly treating the linear potential qE₀z as a standard quadratic degree of freedom (yielding 3kT) or ignoring the spatial potential energy entirely (yielding 5/2 kT or 3/2 kT).
The trap exposes the misconception that equipartition applies uniformly to all potential fields, whereas it strictly requires a quadratic dependence in the Hamiltonian; linear fields yield a full kT contribution.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Thermodynamics - Class 11 Part 2 |
| Concept | Equipartition Theorem |
| Difficulty | 5 |
| Cognitive Load | 6 |
| Target Solve Time | 140 sec |
| Access | Free |