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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumMulti-step

JEE Main 4 August 2021, Shift 2, Physics Q12

Question 12 of 90 in this shift, Physics question 12 of 30, Section A.

Consider two thermally insulated vessels filled with air, having volumes (V1\mathrm{V_1}), (V2\mathrm{V_2}), Pressure P1\mathrm{P_1}, P2\mathrm{P_2} and temperature T1\mathrm{T_1}, T2\mathrm{T_2} for vessels 1 and 2 respectively. What is the temperature inside the vessel at equilibrium if Joining valve of vessels 1 and 2 is opened ?
  1. (1)T1T2(P1V1+P2V2)P1V1T2+P2V2T1\frac{T_1T_2(P_1V_1+P_2V_2)}{P_1V_1T_2+P_2V_2T_1}Official answer
  2. (2)T1T2(P1V1−P2V2)P1V1T2−P2V2T1\frac{T_1T_2(P_1V_1-P_2V_2)}{P_1V_1T_2-P_2V_2T_1}
  3. (3)T1T2(P1V1+P2V2)P1V1T1+P2V2T2\frac{T_1T_2(P_1V_1+P_2V_2)}{P_1V_1T_1+P_2V_2T_2}
  4. (4)P1V1+P2V2P_1V_1+P_2V_2

Official answer

Option 1

NTA final key.

Chapter
Kinetic Theory
Topic
First Law of Thermodynamics
Idea tested
Free Expansion of Ideal Gas

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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.