JEE Main · Physics · Thermodynamics

Second Law and Entropy: JEE Main previous year questions

Name: Second Law and Entropy: JEE Main previous year questions
Creator: Lumi

4 questions in the 108 JEE Main shifts Lumi analysed, in 2 of 8 years. Pattern: Occasional. 0 came in 2024–26. Here is how it is asked and which ideas come back.

Questions: 4; in 4 of 108 shifts
Years asked: 2/8; last asked 2022
Chance in a shift: 9%; calibrated model, how we compute it
Weighted estimate: 0.0; model; history: 0.0 a shift on average, typically 0.0–0.1

Key findings

01
Asked in 2 of 8 years with analysed shifts and in 4 of 108 shifts: 4 questions, #194 of 196 topics. Last asked in 2022.
02
100% of its questions since 2020 tested an idea no earlier year had asked; none repeated an idea from the year before.
03
The most repeated idea is Carnot Engine Efficiency, asked 2 times in 2 shifts (2022), most often as “heat absorbed by carnot engine from work”.
04
JEE Main has asked 3 of the 54 ideas in this topic; 50 have never been asked, directly or inside another question.
05
Mostly asked as numerical value (50%); 50% need a numerical answer, 50% are easy and 0% hard.
06
The skill tested most is calculation (50%), then conceptual (50%).

Questions a shift, year by year

Out of the 25 Physics questions in a shift. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift.

Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 2 in 24 shifts · 2022: 2 in 24 shifts · 2023: 0 in 12 shifts · 2024: 0 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Up to 2023: 0.0; a shift, of 25
Since 2024: 0.0; 0.0
Usual gap: 1.0 yrs; between years asking it
Shifts with it: 4/108; 4% of analysed shifts

How it is asked

Difficulty, format and skill

Across all 4 questions on Second Law and Entropy since 2017.

Difficulty

QUESTIONS

Easy2 · 50%
Medium2 · 50%
Hard0 · 0%

Format

Numerical value · 2 Q50%
Two statements · 1 Q25%
Single correct · 1 Q25%

Skill tested

Calculation · 2 Q50%
Conceptual · 2 Q50%

Repeats

New idea, or one asked before?

Each column is a year. Blue questions tested an idea no earlier year had asked; navy ones went back to an idea from an earlier year. 2017 is the first year, so everything in it counts as new. Heights are question counts, and Lumi analysed 1 to 24 shifts a year, so compare the split inside a column rather than heights across years.

’17’20’21’22’23’24’25’26

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

Coverage of the topic

JEE Main has asked 3 of the 54 ideas in this topic. 50 have never been asked yet.

Asked directly3 · 6%
Touched inside another question1 · 2%
Never asked50 · 93%

Ideas come from Lumi’s JEE syllabus map. A never-asked idea is not a safe skip: across all of JEE Main, 22% of questions since 2024 tested an idea no earlier year had asked.

Drill down

Idea, year, question

Every idea JEE Main tested in this topic, with its eight years. Open one to read the questions.

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

Open2 · 50%50%1/82
- 26 Jun ’22 S2 · Q55
  A heat engine operates with the cold reservoir at temperature 324 K. The minimum temperature of the hot reservoir, if the heat engine…
  mediumNumerical valueNew idea
- 27 Jun ’22 S1 · Q51
  In a carnot engine, the temperature of reservoir is $527^\circ$ C and that of sink is 200 K. If the workdone by the engine when it…
  easyNumerical valueNew idea
Open1 · 25%25%1/8
Open1 · 25%25%1/8

Squares are the 8 years with analysed shifts, 2017 to 2026. A number is the questions that year when there is more than one; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker. Share is of the level above.

Ideas

Every idea inside this topic

3 different ideas were tested; 1 came more than once.

Carnot Engine Efficiency2×
heat absorbed by carnot engine from work
Numerical value · 2 shifts · 2 numerical
Extensive Nature of Entropy1×
total entropy of two gas parts after piston removal
Single correct · 1 shift
Second Law Statements1×
statement i/ii on second law of thermodynamics
Two statements · 1 shift

Idea	Times	Shifts	Format	Numerical
Carnot Engine Efficiencyheat absorbed by carnot engine from work	2	2	Numerical valueCalculation	2
Extensive Nature of Entropytotal entropy of two gas parts after piston removal	1	1	Single correctConceptual	–
Second Law Statementsstatement i/ii on second law of thermodynamics	1	1	Two statementsConceptual	–

Times and shifts count every analysed shift. Across JEE Main, 78% of questions since 2024 went back to an idea an earlier year had asked; the rest were new. All repeated ideas

Every question

Second Law and Entropy questions, year by year

The opening words of each question as it appeared in the official paper, with the idea it tested. Open one for its options and the official answer.

JEE Main 20222 questions in 2 shifts

26 Jun, Shift 2Q55
A heat engine operates with the cold reservoir at temperature 324 K. The minimum temperature of the hot reservoir, if the heat engine…
Idea: Carnot Engine Efficiency
New ideaMediumNumerical value
27 Jun, Shift 1Q51
In a carnot engine, the temperature of reservoir is $527^\circ$ C and that of sink is 200 K. If the workdone by the engine when it…
Idea: Carnot Engine Efficiency
New ideaEasyNumerical value

JEE Main 20212 questions in 2 shifts

4 Aug, Shift 2Q13
Given below are two statements : Statement I : Second law of thermodynamics is derived from the fact that it is impossible to run an…
Idea: Second Law Statements
New ideaMediumTwo statements
18 Mar, Shift 2Q11
An ideal gas in a cylinder is separated by a piston in such a way that the entropy of one part is $S_1$ and that of the other part is…
Idea: Extensive Nature of Entropy
New ideaEasySingle correct

Questions from the official JEE Main Paper 1 shifts published by NTA (CBSE for 2017). Questions NTA dropped are left out. Topic and idea tags, counts and notes are Lumi’s.