Statement I : Change in internal energy of a system containing n mole of ideal gas can be written as Δ U = nC v(T f - T i) = nR/γ-1(T f - T i) , where γ = C p/C v . Statement II : Relation between degree of freedom f and γ is γ = 1 + 2/f .

Both A and R are true but R is NOT the correct explanation of A

Both A and R are true and R is the correct explanation of A

Physics · Kinetic Theory of Gases

JEE Main 2026 — 5 April, Morning Shift — Question 7

Statement I : Change in internal energy of a system containing n mole of ideal gas can be written as $\Delta U = nC_v(T_f - T_i) = \frac{nR}{\gamma-1}(T_f - T_i)$ , where $\gamma = C_p/C_v$ . Statement II : Relation between degree of freedom $f$ and $\gamma$ is $\gamma = 1 + \frac{2}{f}$ .

Option A:
Both A and R are true and R is the correct explanation of A
Option B:
Both A and R are true but R is NOT the correct explanation of A
Correct
Option C:
A is true but R is false
Option D:
A is false but R is true

Answer: B

Step-by-step solution

Both statements are correct, but Statement II does not explain Statement I.

Answer key and solution verified before publishing.

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Exam: JEE Main 2026
Paper: 5 April, Morning Shift
Subject: Physics
Chapter: Kinetic Theory of Gases
Topic: Equipartition Law of Energy and Degrees of Freedom