NEET UG · Chemistry · Thermodynamics

First Law of Thermodynamics: NEET previous year questions

8 questions in ten years of NEET, in 7 of 10 papers. Pattern: Every year. Here is how it is asked and which ideas come back.

Asked in 10 years: 8; about 0.8 per paper
Years asked: 7/10; last asked 2026
Chance of a question next paper: 64%; historical rate, how we compute it
Weighted estimate: 0.8; model; history: 0.8 a paper on average, typically 0–1

Key findings

01
Asked in 7 of 10 papers, 8 questions in all: #102 of 204 topics by ten-year total. It comes back every 1.5 years on average.
02
100% of its questions since 2018 tested an idea never asked before; none repeated an idea from the year before.
03
No idea in this topic has been asked twice: every question tested something new.
04
NEET has asked 0 of the 8 ideas in this topic; 0 have never been asked, directly or indirectly.
05
Mostly asked as numerical (38%); 38% easy, 13% hard.

Questions per year

Up to 2023: 0.7; per paper
Since 2024: 0.9; 0.3
Usual gap: 1.5 yrs; between papers asking it
Swing: ±0.6; questions, year to year

How it is asked

Difficulty, format and skill

Across all 8 questions on First Law of Thermodynamics since 2017.

Difficulty

QUESTIONS

341

Easy3 · 38%
Medium4 · 50%
Hard1 · 13%

Format

Numerical · 3 Q38%
Figure-based · 2 Q25%
One-line MCQ · 2 Q25%
Match the lists · 1 Q13%

Skill tested

Calculation · 3 Q38%
Recall · 2 Q25%
Multi-step · 1 Q13%
Data or graph · 1 Q13%
Concept · 1 Q13%

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 0 of the 8 ideas in this topic. 0 have never been asked yet.

Asked directly0 · 0%
Touched inside another question8 · 100%
Never asked0 · 0%

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

1 · 13%13%1/10
- 2017 · Q60
  A gas is allowed to expand in a well insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L…
  mediumNumericalNew idea
1 · 13%13%1/10
1 · 13%13%1/10
1 · 13%13%1/10
1 · 13%13%1/10
1 · 13%13%1/10
1 · 13%13%1/10
1 · 13%13%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; none came more than once.

Work in Cyclic Processes1×
true statement selection on thermodynamic cycle
Figure-based · 6% next
Reversible Isothermal Work1×
numerical
Numerical · 6% next
Thermodynamic Process Types1×
match list on thermodynamic processes
Match the lists · 6% next
Work as Area Under a p-V Curve1×
graph interpretation of work done
Figure-based · 4% next
Heat Capacities1×
recall relation between heat capacities
One-line MCQ · 4% next
Free Expansion of an Ideal Gas1×
correct option on thermodynamic process
One-line MCQ · 4% next
Work Against Constant External Pressure1×
numerical
Numerical · 4% next
First Law: Delta U = q + w1×
numerical
Numerical · 4% next

Idea	Times	Format	Chance next	Foundation for
Work in Cyclic Processestrue statement selection on thermodynamic cycle	1	Figure-basedMulti-step	6%	–
Reversible Isothermal Worknumerical	1	NumericalCalculation	6%	–
Thermodynamic Process Typesmatch list on thermodynamic processes	1	Match the listsRecall	6%	–
Work as Area Under a p-V Curvegraph interpretation of work done	1	Figure-basedData or graph	4%	–
Heat Capacitiesrecall relation between heat capacities	1	One-line MCQRecall	4%	–
Free Expansion of an Ideal Gascorrect option on thermodynamic process	1	One-line MCQConcept	4%	–
Work Against Constant External Pressurenumerical	1	NumericalCalculation	4%	–
First Law: Delta U = q + wnumerical	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

First Law 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 20261 question

Q69
Consider the reversible processes for 1.0 mol of an ideal gas as shown in the figure. [Figure: Processes 2 and 4 are adiabatic] $w_1$ ,…
Idea: Work in Cyclic Processes
New ideaHardFigure-based · figure

NEET 20242 questions

Q53
Match List I with List II. List I (Process) | List II (Conditions) A. Isothermal process | I. No heat exchange B. Isochoric process | II.…
Idea: Thermodynamic Process Types
New ideaEasyMatch the lists
Q91
The work done during reversible isothermal expansion of one mole of hydrogen gas at 25°C from pressure of 20 atmosphere to 10 atmosphere…
Idea: Reversible Isothermal Work
New ideaMediumNumerical

NEET 20221 question

Q75
Which of the following p-V curve represents maximum work done ?
Idea: Work as Area Under a p-V Curve
New ideaMediumFigure-based · figure

NEET 20211 question

Q75
Which one among the following is the correct option for right relationship between $C_P$ and $C_V$ for one mole of ideal gas ?
Idea: Heat Capacities
New ideaEasyOne-line MCQ

NEET 20201 question

Q104
The correct option for free expansion of an ideal gas under adiabatic condition is :
Idea: Free Expansion of an Ideal Gas
New ideaMediumOne-line MCQ

NEET 20191 question

Q51
Under isothermal condition, a gas at 300 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by…
Idea: Work Against Constant External Pressure
New ideaEasyNumerical

NEET 20171 question

Q60
A gas is allowed to expand in a well insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L…
Idea: First Law: Delta U = q + w
MediumNumerical

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