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Thermodynamics

JEE Mains Physics. Try each one first, then open its answer.

Top 10 JEE Mains PYQs to practise first

The questions and kinds of question asked most often come first. Each one says how often and in which papers.

  1. Question 1

    This type asked 11 times: 2021 Paper 3, 2021 Paper 24, 27 Jun 2022, 26 Jul 2022, 28 Jul 2022, 31 Jan 2023, 1 Feb 2024, 8 Apr 2024, 24 Jan 2025, 21 Jan 2026 S2, 2 Apr 2026 S1. This one: 2 Apr 2026 S1 See all 11 of this type

    8
    Heat is supplied to a diatomic gas at constant pressure. Then the ratio of ΔQ:ΔU:ΔW\Delta Q:\Delta U:\Delta W is ____\_\_\_\_ .

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  2. Question 2

    This type asked 7 times: 2021 Paper 17, 2021 Paper 23, 1 Feb 2023, 4 Apr 2024, 9 Apr 2024, 2 Apr 2026 S1, 8 Apr 2026 S2. This one: 8 Apr 2026 S2 See all 7 of this type

    11
    Initial pressure and volume of a monoatomic ideal gas are P and V. The change in internal energy of this gas in adiabatic expansion to volume Vfinal =27 VV_{\text{final~}}= 27\text{ }V is ____\_\_\_\_ J.

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  3. Question 3

    This type asked 7 times: 2021 Paper 7, 2021 Paper 21, 14 Jun 2022, 26 Jun 2022, 27 Jun 2022, 29 Jun 2022, 8 Apr 2023. This one: 8 Apr 2023 See all 7 of this type

    102
    Work done by a Carnot engine operating between temperatures 127∘C127^{\circ}C and 27∘C27^{\circ}C is 2 kJ2\text{ }kJ. The amount of heat transferred to the engine by the reservoir is:

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  4. Question 4

    This type asked 6 times: 2021 Paper 1, 25 Jan 2023, 11 Apr 2023, 23 Jan 2025, 4 Apr 2025, 7 Apr 2025. This one: 7 Apr 2025 See all 6 of this type

    92
    Match List-I with List-II.
    List-IList-II
    (A) Isothermal(I) ΔW\Delta W (work done) =0= 0
    (B) Adiabatic(II) ΔQ\Delta Q (supplied heat) =0= 0
    (C) Isobaric(III) ΔU\Delta U (change in internal energy) ≠0\neq 0
    (D) Isochoric(IV) ΔU=0\Delta U = 0
    Choose the correct answer from the options given below:

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  5. Question 5

    This type asked 6 times: 2021 Paper 15, 2021 Paper 22, 14 Jun 2022, 28 Jul 2022, 25 Jan 2023, 1 Feb 2023. This one: 1 Feb 2023 See all 6 of this type

    98
    A Carnot engine operating between two reservoirs has efficiency 13\frac{1}{3}. When the temperature of cold reservoir raised by xx, its efficiency decreases to 16\frac{1}{6}. The value of xx, if the temperature of hot reservoir is 99∘C99^{\circ}C, will be:

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  6. Question 6

    This type asked 5 times: 2021 Paper 11, 29 Jul 2022, 31 Jan 2023, 29 Jan 2024, 23 Jan 2025. This one: 23 Jan 2025 See all 5 of this type

    93
    Using the given P-V diagram, the work done by an ideal gas along the path ABCD is-

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  7. Question 7

    Asked 4 times: 27 Jun 2022*, 1 Feb 2024*, 8 Apr 2024, 21 Jan 2026 S2 (* = numbers or wording changed that year) See all 4 times it was asked

    25
    A diatomic gas (γ=1.4)(\gamma = 1.4) does 100 J of work when it is expanded isobarically. Then the heat given to the gas ____\_\_\_\_ J.

  8. Question 8

    This type asked 4 times: 2021 Paper 11, 27 Jan 2024, 21 Jan 2026 S1, 2 Apr 2026 S2. This one: 2 Apr 2026 S2 See all 4 of this type

    23
    5 moles of unknown gas is heated at constant volume from 10∘C10^{\circ}C to 20∘C20^{\circ}C. The molar specific heat of this gas at constant pressure cp=8cal/mol. ∘Cc_{p} = 8cal/mol.\ ^{\circ}C and R=8.36 J/mol. ∘CR = 8.36\text{ }J/mol.\ ^{\circ}C. The change in the internal energy of the gas is ____\_\_\_\_ calorie.

  9. Question 9

    This type asked 4 times: 15 Apr 2023, 5 Apr 2024, 24 Jan 2025, 28 Jan 2026 S2. This one: 28 Jan 2026 S2 See all 4 of this type

    22
    A thermodynamic system is taken through the cyclic process ABC as shown in the figure. The total work done by the system during the cycle ABC is ____\_\_\_\_ J.

  10. Question 10

    This type asked 4 times: 29 Jul 2022, 23 Jan 2025, 3 Apr 2025, 22 Jan 2026 S1. This one: 22 Jan 2026 S1 See all 4 of this type

    16
    The volume of an ideal gas increases 8 times and temperature becomes (1/4)th (1/4)^{\text{th~}} of initial temperature during a reversible change. If there is no exchange of heat in this process ( ΔQ=0\Delta Q = 0 ) then identify the gas from the following options (Assuming the gases given in the options are ideal gases) :

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