JEE Main · 2026 · 06 Apr 2026 · Shift 2 · Heat & Thermodynamics

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If 2 mole of an ideal monoatomic gas at temperature T, is mixed with 6 mole of another ideal monoatomic gas at temperature 2T then the temperature of mixture is:

(A) $\frac{5}{2} T$
(B) $\frac{5}{4} T$
(C) $\frac{7}{2} T$
(D) $\frac{7}{4} T$ ✓ Correct

Answer: (D)

Solution

Mixing at constant volume conserves internal energy, and since both gases are monoatomic with the same

C_{v}

, the mixture temperature is

T_{mi x} = \frac{n _{1} T _{1} + n _{2} T _{2}}{n _{1} + n _{2}} = \frac{2 T + 6 ( 2 T )}{2 + 6} = \frac{14 T}{8} = \frac{7 T}{4}

JEE Main · 2026 · 06 Apr 2026 · Shift 2 · Single correct option

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