NEET UG · Physics · Thermodynamics

Laws of Thermodynamics: NEET previous year questions

10 questions in ten years of NEET, in 8 of 10 papers. Pattern: Every year. Here is how it is asked and which ideas come back.

Asked in 10 years: 10; about 1.0 per paper
Years asked: 8/10; last asked 2026
Chance of a question next paper: 64%; historical rate, how we compute it
Weighted estimate: 1.1; model; history: 1.0 a paper on average, typically 0–2

Key findings

01
Asked in 8 of 10 papers, 10 questions in all: #76 of 204 topics by ten-year total. It comes back every 1.3 years on average.
02
78% of its questions since 2018 tested an idea never asked before; none repeated an idea from the year before.
03
The most repeated idea is First Law in Isobaric Processes, asked 2 times (2018, 2025), usually as “ratio of work to heat in isobaric process of monatomic gas”.
04
NEET has asked 8 of the 85 ideas in this topic; 68 have never been asked, directly or indirectly.
05
Mostly asked as figure-based (40%); 50% easy, 0% hard, and up from 0.8 to 1.3 questions a paper since 2024.

Questions per year

Up to 2023: 0.8; per paper
Since 2024: 1.3; +0.5
Usual gap: 1.3 yrs; between papers asking it
Swing: ±0.6; questions, year to year

Revise first

Adiabatic Work Calculation (2026); First Law in Cyclic Processes (2026); First Law in Isobaric Processes (2018 2025)

How it is asked

Difficulty, format and skill

Across all 10 questions on Laws of Thermodynamics since 2017.

Difficulty

QUESTIONS

Easy5 · 50%
Medium5 · 50%
Hard0 · 0%

Format

Figure-based · 4 Q40%
Numerical · 3 Q30%
One-line MCQ · 2 Q20%
Match the lists · 1 Q10%

Skill tested

Data or graph · 3 Q30%
Calculation · 2 Q20%
Multi-step · 2 Q20%
Concept · 1 Q10%
Recall · 1 Q10%
Figure reading · 1 Q10%

Repeats

New idea, or one asked before?

Each column is a paper. Blue questions tested an idea NEET had not asked before; navy ones went back to an idea from an earlier paper. 2017 is the first paper, so everything in it counts as new.

’17’18’19’20’21’22’23’24’25’26

Idea asked for the first time
Idea asked in an earlier paper

Coverage of the topic

NEET has asked 8 of the 85 ideas in this topic. 68 have never been asked yet.

8968

Asked directly8 · 9%
Touched inside another question9 · 11%
Never asked68 · 80%

Ideas come from Lumi’s syllabus map of NCERT. A never-asked idea is not a safe skip: most new questions come from exactly these.

Drill down

Idea, year, question

Every idea NEET tested in this topic, with its ten papers. Open one to read the questions.

ideaAskedShareYears’17’18’19’20’21’22’23’24’25’26

Repeated2 · 20%20%2/10
- 2025 · Q41
  Two gases $A$ and $B$ are filled at the same pressure in separate cylinders with movable pistons of radius $r_A$ and $r_B$ , respectively.…
  mediumNumerical
- 2018 · Q1
  The volume (V) of a monatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat…
  mediumFigure-basedNew idea
Repeated2 · 20%20%2/10
1 · 10%10%1/10
1 · 10%10%1/10
1 · 10%10%1/10
1 · 10%10%1/10
1 · 10%10%1/10
1 · 10%10%1/10

Squares are the ten papers, 2017 to 2026; darker means more questions. Share is of the level above.

Ideas

Every idea inside this topic

8 different ideas were tested; 2 came more than once. Work and First Law from P-V Graphs is the foundation for 7 other ideas in the syllabus.

First Law in Isobaric Processes2×
ratio of work to heat in isobaric process of monatomic gas
Figure-based · 6% next
Slopes on P-V Diagrams2×
identify adiabatic curve on p-v graph
Figure-based · 6% next
Adiabatic Work Calculation1×
numerical
Numerical · 6% next
First Law in Cyclic Processes1×
numerical
Figure-based · 6% next · foundation for 6
Work and First Law from P-V Graphs1×
numerical
Figure-based · 6% next · foundation for 7
First Law in Free Expansion1×
identify process type in free expansion
One-line MCQ · 4% next
First Law in Adiabatic Processes1×
identify process type from heat exchange
One-line MCQ · 4% next · foundation for 3
First Law in Boiling1×
numerical
Numerical · 4% next

Idea	Times	Format	Chance next	Foundation for
First Law in Isobaric Processesratio of work to heat in isobaric process of monatomic gas	2	Figure-basedMulti-step	6%	–
Slopes on P-V Diagramsidentify adiabatic curve on p-v graph	2	Figure-basedData or graph	6%	–
Adiabatic Work Calculationnumerical	1	NumericalCalculation	6%	–
First Law in Cyclic Processesnumerical	1	Figure-basedData or graph	6%	6 ideas
Work and First Law from P-V Graphsnumerical	1	Figure-basedData or graph	6%	7 ideas
First Law in Free Expansionidentify process type in free expansion	1	One-line MCQConcept	4%	–
First Law in Adiabatic Processesidentify process type from heat exchange	1	One-line MCQRecall	4%	3 ideas
First Law in Boilingnumerical	1	NumericalCalculation	4%	–

Chance next is the historical rate at which an idea with this record came back in the following paper. It is low for every idea, which is why learning the topic beats memorising past questions. All repeated ideas

Every question

Laws of Thermodynamics questions, year by year

The opening words of each question as it appeared in the official paper, with the idea it tested.

NEET 20262 questions

Q17
In an adiabatic expansion, the temperature of one mole of an ideal monatomic gas ( $\gamma=5/3$ ) decreases from 60K to 50K. The work done…
Idea: Adiabatic Work Calculation
New ideaEasyNumerical
Q39
One mole of an ideal monatomic gas undergoes a cyclic process as shown in the figure. The total heat supplied to the gas is :
Idea: First Law in Cyclic Processes
New ideaEasyFigure-based · figure

NEET 20251 question

Q41
Two gases $A$ and $B$ are filled at the same pressure in separate cylinders with movable pistons of radius $r_A$ and $r_B$ , respectively.…
Idea: First Law in Isobaric Processes
MediumNumerical

NEET 20241 question

Q7
A thermodynamic system is taken through the cycle $abcda$ . The work done by the gas along the path $bc$ is :
Idea: Work and First Law from P-V Graphs
New ideaEasyFigure-based · figure

NEET 20221 question

Q24
An ideal gas undergoes four different processes from the same initial state as shown in the figure below. Those processes are adiabatic,…
Idea: Slopes on P-V Diagrams
MediumFigure-based · figure

NEET 20201 question

Q141
Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and…
Idea: First Law in Free Expansion
New ideaEasyOne-line MCQ

NEET 20191 question

Q40
In which of the following processes, heat is neither absorbed nor released by a system ?
Idea: First Law in Adiabatic Processes
New ideaEasyOne-line MCQ

NEET 20182 questions

Q1
The volume (V) of a monatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat…
Idea: First Law in Isobaric Processes
New ideaMediumFigure-based · figure
Q45
A sample of 0.1 g of water at 100°C and normal pressure ( $1.013\times10^{5}$ Nm $^{-2}$ ) requires 54 cal of heat energy to convert to steam…
Idea: First Law in Boiling
New ideaMediumNumerical

NEET 20171 question

Q16
Thermodynamic processes are indicated in the following diagram. Match the following Column-1 | Column-2 P. Process I | a. Adiabatic Q.…
Idea: Slopes on P-V Diagrams
MediumMatch the lists · figure

Questions from the official NEET UG papers published by NTA (CBSE before 2019). Topic and idea tags, counts and notes are Lumi’s.