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Given below are two statements:
Statement I: In a diatomic molecule, the rotational energy at a given temperature obeys Maxwell's distribution.
Statement II: In a diatomic molecule, the rotational energy at a given temperature equals the translational kinetic energy for each molecule.
In the light of the above statements, choose the correct answer from the options given below:
- Statement I is false but Statement II is true.
- Both Statement I and Statement II are false.
- Both Statement I and Statement II are true.
- Statement I is true but Statement II is false.
Correct answer: Both Statement I and Statement II are false.
Solution
Rotational energy follows a Boltzmann (not Maxwell) distribution; Maxwell's distribution describes molecular speeds, so Statement I is false. Rotational energy does not equal translational KE per molecule (translational uses 3 degrees of freedom = (3/2)kT, rotational of a diatomic uses 2 = kT, equal only on average per degree of freedom), so Statement II is false.
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