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JEE Main 2026 (4 Apr, Shift 1) · Degrees of Freedom & Internal Energy

Degrees of Freedom & Internal Energy question from JEE Main 2026 (4 Apr, Shift 1)

Q3JEE Main 2026 · 4 APR · SHIFT 1Medium

Degrees of Freedom & Internal Energy

One gas of n1n_1 mole of molecules at temperature T1T_1, volume V1V_1, and pressure P1P_1, and another gas of n2n_2 mole of molecules at temperature T2T_2, volume V2V_2, and pressure P2P_2, are mixed resulting in pressure PP and volume VV of the mixture. The temperature of the mixture is ______.

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Answer: (b)

  1. Total moles are conserved: n=n1+n2n = n_1 + n_2, with n=PVRTn = \frac{PV}{RT}.
  2. PVRT=P1V1RT1+P2V2RT2\frac{PV}{RT} = \frac{P_1V_1}{RT_1} + \frac{P_2V_2}{RT_2}
  3. T=PVP1V1/T1+P2V2/T2=T1T2PVT2P1V1+T1P2V2T = \frac{PV}{P_1V_1/T_1 + P_2V_2/T_2} = \frac{T_1T_2PV}{T_2P_1V_1 + T_1P_2V_2}
  4. So the answer is (b).
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