Kinetic Theory

JEE Main level, single correct, medium

3 of 168

Question 3 of 168

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 _____.

Show answer and solution

Answer: (B) T1T2PV/(T2P1V1+T1P2V2)T_1 T_2 PV/(T_2 P_1 V_1 + T_1 P_2 V_2)

From the ideal gas equation, the number of moles of the first gas is n1=P1V1RT1n_1 = \dfrac{P_1 V_1}{R T_1} and the number of moles of the second gas is n2=P2V2RT2n_2 = \dfrac{P_2 V_2}{R T_2}.

For the mixture, the total number of moles is
n=n1+n2n = n_1 + n_2.

Applying the ideal gas equation for the mixture:


PV=nRTP V = n R T

T=PVnRT = \dfrac{P V}{n R}

Substituting the values of
n1n_1 and n2n_2:

T=PV(P1V1RT1+P2V2RT2)RT = \dfrac{P V}{\left( \dfrac{P_1 V_1}{R T_1} + \dfrac{P_2 V_2}{R T_2} \right) R}

T=PVP1V1T1+P2V2T2T = \dfrac{P V}{\dfrac{P_1 V_1}{T_1} + \dfrac{P_2 V_2}{T_2}}

T=T1T2PVP1V1T2+P2V2T1T = \dfrac{T_1 T_2 P V}{P_1 V_1 T_2 + P_2 V_2 T_1}

Answer:
T1T2PV/(T2P1V1+T1P2V2)T_1 T_2 PV/(T_2 P_1 V_1 + T_1 P_2 V_2)

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.

More Physics practice

JEE Main Physics practice question on Kinetic Theory (Gas Laws), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.