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Saturday, 31 October

JEE Main 2026 · PhysicsMultiple choiceSingle correctMediumMulti-step

JEE Main 8 April 2026, Shift 2, Physics Q35

Question 35 of 75 in this shift, Physics question 10 of 25, Section A.

One mole of diatomic gas having rotational modes only is kept in a cylinder with a piston system. The cross-section area of the cylinder is 4 cm2^2. The gas is heated slowly to raise the temperature by 1.2 ∘^\circC during which the piston moves by 25 mm. The amount of heat supplied to the gas is ________ J. (Atmospheric pressure = 100 kPa, R=8.3R = 8.3 J/mol. K) (Neglect mass of the piston)
  1. (1)24.8Official answer
  2. (2)25Official answer
  3. (3)15.04
  4. (4)29.98

Official answer

Options 1 and 2

NTA final key: multiple options accepted. Either option scored full marks.

Chapter
Thermodynamics
Topic
First Law of Thermodynamics
Idea tested
Heat in Isochoric and Isobaric Processes

Same idea in other shifts

Asked 5× in all
  1. 1 Feb 2024, Shift 2 · Q38A diatomic gas (γ=1.4\gamma = 1.4) does 200 J of work when it is expanded isobarically. The heat given to the gas in the process is :EasySingle correct
  2. 27 Jun 2022, Shift 2 · Q53A diatomic gas (γ\gamma = 1.4) does 400J of work when it is expanded isobarically. The heat given to the gas in the process is __________…EasyNumerical value
  3. 29 Jun 2022, Shift 1 · Q35A cylinder of fixed capacity of 44.8 litres contains helium gas at standard temperature and pressure. The amount of heat needed to raise…EasySingle correct
  4. 25 Feb 2021, Shift 1 · Q18A diatomic gas, having CP=72RC_P=\frac{7}{2}R and CV=52RC_V=\frac{5}{2}R, is heated at constant pressure. The ratio dU : dQ : dW :EasySingle correct

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.