What does Thermodynamics cover for NEET Physics?

7 lessons: Concept of Temperature, First Law Thermodynamics, Heat Work Internal Energy, Isothermal Adiabatic Processes, Reversible Irreversible Processes, Second Law Thermodynamics and Thermal Equilibrium Zeroth Law.

How often has Thermodynamics come up in NEET past papers?

Our set of verified past papers has 5 questions from this unit, from NEET 2023, 2024, 2025 and 2026. Each is answered against the official NTA key.

Is the Thermodynamics material free?

Yes. All 7 lessons and 56 practice questions are free, with no login needed.

Thermodynamics

7 lessons

Topic index in NCERT order

7 of 7 lessons by the NCERT chapter they teach from, in book order. The page is the first printed page of your NCERT book the lesson cites; PYQs are the past NEET questions on that topic.

Class 11 Physics, Chapter 11

Concept of Temperaturep. 2280 PYQs
Thermal Equilibrium Zeroth Lawp. 2280 PYQs
First Law Thermodynamicsp. 2302 PYQs
Heat Work Internal Energyp. 2300 PYQs
Isothermal Adiabatic Processesp. 2352 PYQs
Reversible Irreversible Processesp. 2360 PYQs
Second Law Thermodynamicsp. 2361 PYQ

Concept of Temperature

8 MCQsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

First Law Thermodynamics

8 MCQs2 PYQs7 revision cardsWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Heat Work Internal Energy

8 MCQs2 revision cardsWorked example

Easy Recall (3)Calculation (2)Direct Application (3)

Isothermal Adiabatic Processes

8 MCQs2 PYQs3 revision cardsWorked example

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Reversible Irreversible Processes

8 MCQsWorked example

Easy Recall (3)Concept Trap (2)Direct Application (3)

Second Law Thermodynamics

8 MCQs1 PYQsWorked example

Easy Recall (3)Concept Trap (2)Direct Application (3)

Thermal Equilibrium Zeroth Law

8 MCQsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (2)

Past-paper questions from this unit

5 questions from NEET 2023, 2024, 2025, 2026. Answers verified against NTA official keys.

By year in our set: 2023 (1) · 2024 (1) · 2025 (1) · 2026 (2)

Lesson: Isothermal Adiabatic Processes

NEET 2026

In an adiabatic expansion, the temperature of one mole of an ideal monatomic gas (γ = 5/3) decreases from 60 K to 50 K. The work done by the gas in the process is : (Take the universal gas constant as R = 8.3 J mol⁻¹ K⁻¹)

141.5 J

283 J

3124.5 J

4166 J

NTA Answer: Option 3(final)

Report an error · Every fix is public: corrections log

Lesson: Isothermal Adiabatic Processes

NEET 2026

One mole of an ideal monatomic gas undergoes a cyclic process as shown in the figure. The total heat supplied to the gas is :

1400 J

2500 J

3600 J

4800 J

NTA Answer: Option 3(final)

Report an error · Every fix is public: corrections log

Lesson: First Law Thermodynamics

NEET 2025

A container has two chambers of volumes V 1 = 2 litres and V 2 = 3 litres separated by a partition made of a thermal insulator. The chambers contain n 1 = 5 and n 2 = 4 moles of ideal gas at pressures p 1 = 1 atm and p 2 = 2 atm, respectively. When the partition is removed, the mixture attains an equilibrium pressure of

11.8 atm

21.3 atm

31.6 atm

41.4 atm

NTA Answer: Option 3(final)

Report an error · Every fix is public: corrections log

Lesson: First Law Thermodynamics

NEET 2024Revised key

A thermodynamic system is taken through the cycle abcda. The work done by the gas along the path bc is:

1Zero

230 J

3–90 J

4–60 J

NTA Answer: Option 1(revised_final)

Report an error · Every fix is public: corrections log

Lesson: Second Law Thermodynamics

NEET 2023

A Carnot engine has an efficiency of 50% when its source is at a temperature 327°C. The temperature of the sink is

115°C

2100°C

3200°C

427°C

NTA Answer: Option 4(final)

Report an error · Every fix is public: corrections log

Exam traps and common mistakes in this unit

Lesson: Isothermal Adiabatic Processes

Trap

Adiabatic vs isothermal P-V curve

Category: Graph Interpretation

Student misidentifies which P-V curve is adiabatic (steeper) vs isothermal.

When it triggers

P-V graph showing one or more processes; question asks for process type.

How to avoid

Adiabatic curve is STEEPER than isothermal at the same point (slope ratio = γ). Adiabat: PV^γ; isotherm: PV = const.

Lesson: Isothermal Adiabatic Processes

Mistake

Identifies adiabatic curve as gentler than isothermal on P-V diagram (or vice versa).

Root cause: graph misread

Correction

Adiabatic curve is STEEPER than isothermal at the same P-V point. Slope ratio at same point: adiabatic / isothermal = γ. Memorise: 'adiabatic angles down sharper'.

Formulas in this unit

Lesson: First Law Thermodynamics

First law of thermodynamics

Δ U = Q - W

Change in internal energy = heat ADDED minus work DONE BY the system. Energy conservation including thermal energy.

Symbol	Quantity	SI Unit
Delta_U	change in internal energy	J
Q	heat added to system	J
W	work done BY system	J

Valid when

Closed system (no mass exchange)
Sign convention: Q>0 heat in, W>0 system does work

Lesson: Heat Work Internal Energy

Mayer's relation (Cp - Cv = R)

C_{p} - C_{v} = R

For ideal gas: difference of molar specific heats equals gas constant R. Useful for converting between Cp and Cv.

Symbol	Quantity	SI Unit
Cp	molar specific heat at const P	J/mol/K
Cv	molar specific heat at const V	J/mol/K
R	8.314	J/mol/K

Valid when

Ideal gas
Per mole basis

Lesson: Isothermal Adiabatic Processes

Adiabatic relations for ideal gas

P V^{γ} = const; T V^{γ - 1} = const

Relations holding during reversible adiabatic process. gamma = Cp/Cv.

Symbol	Quantity	SI Unit
P	pressure	Pa
V	volume	m^3
T	temperature	K
gamma	adiabatic index	-

Valid when

Q = 0 (no heat exchange)
Quasi-static (reversible)
Ideal gas

Lesson: Isothermal Adiabatic Processes

Work done in isothermal process (ideal gas)

W = n R T ln \frac{V _{f}}{V _{i}}

Work done by ideal gas during isothermal expansion. Q = W (since Delta_U = 0). Reverse for compression.

Symbol	Quantity	SI Unit
n	moles	mol
R	gas constant 8.314	J/mol/K
T	temperature	K
V_i, V_f	initial/final volume	m^3

Valid when

Ideal gas
Quasi-static (reversible) isothermal

NEET question patterns in this unit

Lesson: First Law Thermodynamics

Cyclic process: net Q = net W (since Delta_U cycle = 0). Compute work/heat over each segment.

Multi StepMedium

Common distractors

forgets net zero cycle

Computes only one segment's W

Lesson: Isothermal Adiabatic Processes

Identify P-V diagram or temperature behaviour of isothermal vs adiabatic process. Adiabatic: PV^gamma; isothermal: PV.

InterpretationMedium

Common distractors

swaps adiabatic isothermal curves

Confuses which curve is steeper

Questions about this unit

What does Thermodynamics cover for NEET Physics?: 7 lessons: Concept of Temperature, First Law Thermodynamics, Heat Work Internal Energy, Isothermal Adiabatic Processes, Reversible Irreversible Processes, Second Law Thermodynamics and Thermal Equilibrium Zeroth Law.
How often has Thermodynamics come up in NEET past papers?: Our set of verified past papers has 5 questions from this unit, from NEET 2023, 2024, 2025 and 2026. Each is answered against the official NTA key.
Is the Thermodynamics material free?: Yes. All 7 lessons and 56 practice questions are free, with no login needed.