Thermodynamics — JEE Main PYQs & Practice Questions

Thermodynamics is a Physics chapter in the JEE Main syllabus. This page brings together 158 previous-year and practice questions on Thermodynamics, organised into 6 topics: Second Law and Entropy, Carnot Engine, Thermodynamic Processes, First Law of Thermodynamics, Work Done in Processes and Heat Engines and Efficiency. Most questions come with a step-by-step solution you can work through free in PrepWiser.

Download Thermodynamics JEE Main PYQs as a free PDF (with answer key)

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Chapter weightage: how many questions each chapter had per shift in the 2024–26 papers.

Second Law and Entropy

• A heat engine that converts all absorbed heat into work without any waste violates the…
• For any process in an isolated system, the entropy:
• If minimum possible work is done by a refrigerator in converting 100 grams of water at…
• Water of mass m gram is slowly heated to increase the temperature from T₁ to T_γ. The…
• The entropy of any system is given by S = α ²β ln [ (μ kR)/(Jβ ²) + 3 ] where α and β…
• The change in entropy for a reversible isothermal expansion of n moles of an ideal gas…
• An ideal gas in a cylinder is separated by a piston in such a way that the entropy of…
• Which of the following gives a reversible operation?

Carnot Engine

• A heat engine has an efficiency of 1/6. When the temperature of sink is reduced by 62°C…
• A Carnot engine operating between two reservoirs has efficiency 1/3. When the…
• A Carnot engine takes 5000 kcal of heat from a reservoir at 727°C and gives heat to a…
• A Carnot engine has efficiency of 50 %. If the temperature of sink is reduced by 40° C…
• The maximum possible efficiency of a heat engine working between a hot reservoir at T₁…
• A heat engine operates with the cold reservoir at temperature 324 K. The minimum…
• Two ideal Carnot engines operate in cascade (all heat given up by one engine is used by…
• A Carnot engine with efficiency 50% takes heat from a source at 600 K. In order to…
• Let η₁ is the efficiency of an engine at T₁=447° C and T₂=147° C while η₂ is the…
• Two Carnot engines A and B operate in series such that engine A absorbs heat at T₁ and…
• Work done by a Carnot engine operating between temperatures 127° C and 27° C is 2 kJ…
• In 1ˢᵗ case, Carnot engine operates between temperatures 300 K and 100 K. In 2ⁿᵈ case…
• A Carnot engine (E) is working between two temperatures 473 K and 273 K . In a new…
• A Carnot engine operates between 400 K and 300 K. Its efficiency is:
• A Carnot engine has an efficiency of 40% with hot reservoir at 500 K. The temperature of…
• A Carnot engine whose heat sinks at 27°C, has an efficiency of 25%. By how many degrees…
• A carnot engine having an efficiency of 1/10 is being used as a refrigerator. If the…
• 300 cal. of heat is given to a heat engine and it rejects 225 cal. If source temperature…
• A Carnot's engine working between 400 K and 800 K has a work output of 1200 J per cycle…
• An engine operating between the boiling and freezing points of water will have A…

Thermodynamic Processes

• For an adiabatic expansion of an ideal gas, the fractional change in its pressure is…
• The internal energy of a monoatomic gas is 3nRT. One mole of helium is kept in a…
• A diatomic gas (γ=1.4) does 100 J of work when it is expanded isobarically. Then the…
• A diatomic gas (γ=1.4) does 100 J of work in an isobaric expansion. The heat given to…
• During an adiabatic process, the pressure of a gas is found to be proportional to the…
• Given below are two statements. One is labelled as Assertion (A) and the other is…
• For an ideal gas the instantaneous change in pressure 'p' with volume 'v' is given by…
• An ideal gas goes from an initial state to final state. During the process, the pressure…
• Initial pressure and volume of a monoatomic ideal gas are P and V. The change in…
• An ideal gas is expanding such that PT³ = constant. The coefficient of volume expansion…
• Match the thermodynamic processes taking place in a system with the correct conditions…
• In an isothermal process for an ideal gas:
• The magnitude of heat exchanged by a system for the given cyclic process ABCA (as shown…
• One mole of an ideal diatomic gas expands from volume V to 2V isothermally at a…
• Given below are two statements. One is labelled as Assertion (A) and the other is…
• The Thermodynamic process, in which internal energy of the system remains constant is
• A vessel contains 0.15 m³ of a gas at pressure 8 bar and temperature 140 °C with cₚ=3R…
• In the following p-V diagram the equation of state along the curved path is given by…
• In the reported figure, there is a cyclic process ABCDA on a sample of 1 mol of a…
• A monoatomic gas at pressure P and volume V is suddenly compressed to one eighth of its…

First Law of Thermodynamics

• The specific heat at constant pressure of a real gas obeying P V²=R T equation is:
• In thermodynamics, heat and work are :
• 1 g of a liquid is converted to vapour at 3 × 10⁵ Pa pressure. If 10% of the heat…
• The temperature of 1 mole of an ideal monoatomic gas is increased by 50° C at constant…
• A diatomic gas (γ=1.4) does 200 J of work when it is expanded isobarically. The heat…
• The temperature of 3.00 mol of an ideal diatomic gas is increased by 40.0°C without…
• 0.08 kg air is heated at constant volume through 5° C. The specific heat of air at…
• The pressure of a gas changes linearly with volume from A to B as shown in figure. If no…
• The Zeroth law of thermodynamics leads to the definition of:
• 10 mole of oxygen is heated at constant volume from 30°C to 40°C. The change in the…
• A poly-atomic molecule (C_V=3 R, C_P=4 R, where R is gas constant) goes from phase space…
• According to the first law of thermodynamics, if Q is the heat added to a system and W…
• A sample of an ideal gas is taken through the cyclic process ABCA as shown in figure. It…
• Given below are two statements: Statement I: If heat is added to a system, its…
• Heat energy of 735 J is given to a diatomic gas allowing the gas to expand at constant…
• 7 mol of a certain monoatomic ideal gas undergoes a temperature increase of 40 K at…
• 5 moles of unknown gas is heated at constant volume from 10°C to 20°C. The molar…
• A diatomic gas, having Cₚ = 7/2R and Cᵥ = 5/2R, is heated at constant pressure. The…
• A total of 48 J heat is given to one mole of helium kept in a cylinder. The temperature…
• The amount of heat needed to raise the temperature of 4 moles of rigid diatomic gas from…

Work Done in Processes

• An ideal gas has undergone through the cyclic process as shown in the figure. Work done…
• A thermodynamic system is taken from an original state D to an intermediate state E by…
• One mole of an ideal gas at 27° is taken from A to B as shown in the given PV indicator…
• A thermodynamic system is taken from an original state A to an intermediate state B by a…
• A real gas within a closed chamber at 27° C undergoes the cyclic process as shown in…
• The volume V of a given mass of monoatomic gas changes with temperature T according to…
• Three different processes that can occur in an ideal monoatomic gas are shown in the P…
• The P-V diagram of a diatomic ideal gas system going under cyclic process as shown in…
• A litre of dry air at STP expands adiabatically to a volume of 3 litres. If γ = 1.40…
• n mole of a perfect gas undergoes a cyclic process ABCA (see figure) consisting of the…
• A sample of gas at temperature T is adiabatically expanded to double its volume. The…
• A sample of gas at temperature T is adiabatically expanded to double its volume…
• The pressure and volume of an ideal gas are related as PV^(3/2)=K (Constant). The work…
• Using the given P-V diagram, the work done by an ideal gas along the path A B C D is :
• A thermodynamic system is taken through cyclic process. The total work done in the…
• Starting with the same initial conditions, an ideal gas expands from volume V₁ to V₂ in…
• Given below are two statements : Statement I : When μ amount of an ideal gas undergoes…
• The work done by a gas in an isobaric expansion from V₁ to V₂ at pressure P is:
• In a certain thermodynamical process, the pressure of a gas depends on its volume as…

Heat Engines and Efficiency

• A reversible heat engine converts one-fourth of the heat input into work. When the…
• A heat engine is involved with exchange of heat of 1915 J, – 40J, + 125 J and –Q J…
• A refrigerator consumes an average 35W power to operate between temperature -10°C to…
• For an ideal heat engine, the temperature of the source is 127°C. In order to have 60%…
• An engine operates by taking a monoatomic ideal gas through the cycle shown in the…
• Given below are two statements: one is labelled as Assertion A and the other is labelled…

More Physics chapters

• Basic Mathematics for Physics
• Units, Dimensions & Errors
• Rectilinear Motion
• Vectors
• Projectile Motion & Relative Motion
• Newton's Laws of Motion
• Friction
• Circular Motion
• Work, Energy & Power
• Centre of Mass & Linear Momentum
• Collision
• Rotational Motion
• Gravitation
• Simple Harmonic Motion
• Elasticity
• Fluid Mechanics
• Surface Tension
• Thermometry & Calorimetry
• Kinetic Theory of Gases
• Heat Transfer
• Mechanical Waves
• Sound Waves
• Experimental Skills
• Electrostatics I — Charges, Field & Gauss's Law
• Electrostatics II — Potential & Capacitance
• Current Electricity
• Moving Charges & Magnetism
• Magnetism & Matter
• Electromagnetic Induction
• Alternating Current
• Electromagnetic Waves
• Ray Optics
• Wave Optics
• Dual Nature of Radiation & Matter
• Atomic Physics
• Nuclear Physics
• Semiconductors & Electronic Devices
• Communication Systems

Frequently asked questions

How many Thermodynamics questions are there for JEE Main?

PrepWiser has 158 Thermodynamics questions for JEE Main, grouped into 6 topics such as Second Law and Entropy, Carnot Engine and Thermodynamic Processes.

Are these Thermodynamics questions from previous-year JEE Main papers?

Yes — most are genuine previous-year questions from past JEE Main papers, and the rest are practice questions written to match the JEE Main pattern and difficulty.

Where can I see the answers and solutions to these Thermodynamics questions?

Open any Thermodynamics question in PrepWiser (it is free) to attempt it; most come with a step-by-step solution.