Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. 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, T i = initial temperature, T f = final temperature. Statement II: Relation between degree of freedom f and γ (= C p /C v) is (γ = 1 + 2/f). Choose the correct answer from the options given below

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

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

Thermodynamics: JEE Main 2026 Physics question

JEE Main 2026 · 5 Apr, Morning shift · Q32

JEE Main 20265 Apr, Morning shiftPhysicsHardThermodynamics163× since 2002

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. 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 = \frac{C_p}{C_v}

T_i

= initial temperature,

T_f

= final temperature. Statement II: Relation between degree of freedom

f

and

\gamma\ (= C_p/C_v)

\left(\gamma = 1 + \frac{2}{f}\right)

. Choose the correct answer from the options given below

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