JEE Main · Physics · Kinetic Theory
Kinetic Theory of Gases: JEE Main previous year questions
84 questions in the 108 JEE Main shifts Lumi analysed, in 8 of 8 years. Pattern: Asked most years. 22 came in 2024–26. Here is how it is asked and which ideas come back.
- Questions
- 84
- in 80 of 108 shifts
- Years asked
- 8/8
- last asked 2026
- Weighted estimate
- 0.6
- model; history: 0.7 a shift on average, typically 0.5–0.8
Key findings
- 01
Asked in 8 of 8 years with analysed shifts and in 80 of 108 shifts: 84 questions, #12 of 196 topics. It came in every year with analysed shifts.
- 02
39% of its questions since 2020 tested an idea no earlier year had asked; 44 repeated an idea from the year before.
- 03
The most repeated idea is Molecular Speed Types, asked 12 times in 12 shifts (2021, 2022, 2023), most often as “rms speed after temperature change”.
- 04
JEE Main has asked 22 of the 53 ideas in this topic; 26 have never been asked, directly or inside another question.
- 05
Mostly asked as single correct (69%); 13% need a numerical answer, 64% are easy and 0% hard. It went down from 0.8 to 0.5 questions a shift since 2024.
- 06
The skill tested most is calculation (43%), then conceptual (25%).
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: 1 in 1 shift · 2020: 12 in 12 shifts · 2021: 18 in 24 shifts · 2022: 19 in 24 shifts · 2023: 12 in 12 shifts · 2024: 16 in 18 shifts · 2025: 4 in 8 shifts · 2026: 2 in 9 shifts.
- Up to 2023
- 0.8
- a shift, of 25
- Since 2024
- 0.5
- -0.3
- Usual gap
- 1.3 yrs
- between years asking it
- Shifts with it
- 80/108
- 74% of analysed shifts
Recent framings
- statement I/II on ideal gas internal energy
- assertion-reason on kinetic theory of gases
- numerical: ratio of kinetic energies of gases
Revise first
- Kinetic Energy and Temp · asked 2020, 2021, 2022, 2023, 2024, 2025, 2026
- Gamma and Degrees of Freedom · asked 2020, 2021, 2022, 2025, 2026
- Molecular Speed Types · asked 2021, 2022, 2023
How it is asked
Difficulty, format and skill
Across all 84 questions on Kinetic Theory of Gases since 2017.
Difficulty
QUESTIONS- Easy54 · 64%
- Medium30 · 36%
- Hard0 · 0%
Format
SHARE- Single correct · 58 Q69%
- Numerical value · 11 Q13%
- Other · 5 Q6%
- Two statements · 4 Q5%
- Match the list · 3 Q4%
- Assertion–reason · 2 Q2%
- Diagram based · 1 Q1%
Skill tested
SHARE- Calculation · 36 Q43%
- Conceptual · 21 Q25%
- Recall · 11 Q13%
- Application · 10 Q12%
- Multi-step · 5 Q6%
- Data or graph · 1 Q1%
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.
- Idea asked for the first time
- Idea asked in an earlier year
Coverage of the topic
JEE Main has asked 22 of the 53 ideas in this topic. 26 have never been asked yet.
- Asked directly22 · 42%
- Touched inside another question5 · 9%
- Never asked26 · 49%
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
Chapter, idea, question
Every idea JEE Main tested in this topic, with its eight years. Open one to read the questions.
20 ideas inside
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
22 different ideas were tested; 14 came more than once.
rms speed after temperature change
Single correct · 12 shifts · 2 numericalassertion-reason on kinetic theory of gases
Single correct · 11 shifts · 1 numericalstatement i/ii on ideal gas internal energy
Single correct · 9 shiftsrms speed ratio by molar mass
Single correct · 8 shifts · 1 numericalinternal energy of gas mixture
Single correct · 7 shifts · 2 numericalinternal energy of gas in room
Single correct · 6 shifts · 1 numericalmean free path from conditions
Other · 6 shifts · 1 numericaldegrees of freedom of polyatomic molecule
Match the list · 4 shifts · 1 numericaldependence of mean collision time on temperature
Single correct · 3 shiftsadiabatic exponent of gas mixture
Single correct · 2 shiftsratio of gas pressures from mass and molar mass
Single correct · 2 shiftsratio of collision frequency on changing density
Single correct · 2 shiftsenergy of molecules with vibrational degrees of freedom
Single correct · 2 shiftspressure of gas mixture from moles and volume
Numerical value · 2 shifts · 1 numericalratio of specific heat ratios
Numerical value · 1 shift · 1 numericaltemperature for equal rms speeds
Single correct · 1 shiftmean free path at changed temperature
Single correct · 1 shiftassertion-reason on escape velocity and atmosphere
Assertion–reason · 1 shiftdimension of physical quantity from formula
Single correct · 1 shiftorigin of gas pressure in kinetic theory
Single correct · 1 shiftinternal energy of polyatomic gas from degrees of freedom
Single correct · 1 shiftchange in molecule count on heating
Single correct · 1 shift
| Idea | Years asked | Times | Shifts | Format | Numerical |
|---|---|---|---|---|---|
| Molecular Speed Typesrms speed after temperature change | 12 | 12 | Single correctCalculation | 2 | |
| Kinetic Energy and Tempassertion-reason on kinetic theory of gases | 11 | 11 | Single correctCalculation | 1 | |
| Gamma and Degrees of Freedomstatement i/ii on ideal gas internal energy | 9 | 9 | Single correctRecall | – | |
| Molecular Speed Ratiosrms speed ratio by molar mass | 8 | 8 | Single correctCalculation | 1 | |
| Internal Energy of Gas Mixturesinternal energy of gas mixture | 7 | 7 | Single correctCalculation | 2 | |
| Law of Equipartitioninternal energy of gas in room | 6 | 6 | Single correctConceptual | 1 | |
| Mean Free Pathmean free path from conditions | 6 | 6 | OtherConceptual | 1 | |
| Degrees of Freedomdegrees of freedom of polyatomic molecule | 4 | 4 | Match the listRecall | 1 | |
| Relaxation Timedependence of mean collision time on temperature | 3 | 3 | Single correctConceptual | – | |
| Adiabatic Exponent of Gas Mixturesadiabatic exponent of gas mixture | 2 | 2 | Single correctCalculation | – | |
| Avogadro's Hypothesis Applicationratio of gas pressures from mass and molar mass | 2 | 2 | Single correctApplication | – | |
| Collision Frequencyratio of collision frequency on changing density | 2 | 2 | Single correctApplication | – | |
| Vibrational Degrees of Freedomenergy of molecules with vibrational degrees of freedom | 2 | 2 | Single correctApplication | – | |
| Microscopic Dalton's Lawpressure of gas mixture from moles and volume | 2 | 2 | Numerical valueCalculation | 1 | |
| Specific Heat Ratio Formularatio of specific heat ratios | 1 | 1 | Numerical valueCalculation | 1 | |
| Equating Speeds of Different Gasestemperature for equal rms speeds | 1 | 1 | Single correctCalculation | – | |
| Mean Free Path Temperature Dependencemean free path at changed temperature | 1 | 1 | Single correctCalculation | – | |
| Planetary Atmosphere Retentionassertion-reason on escape velocity and atmosphere | 1 | 1 | Assertion–reasonConceptual | – | |
| Van der Waals Pressure Correctiondimension of physical quantity from formula | 1 | 1 | Single correctApplication | – | |
| Gas Pressure Derivationorigin of gas pressure in kinetic theory | 1 | 1 | Single correctRecall | – | |
| Linear vs Non-Linear Polyatomic DOFinternal energy of polyatomic gas from degrees of freedom | 1 | 1 | Single correctConceptual | – | |
| Number Density Calculationschange in molecule count on heating | 1 | 1 | Single correctCalculation | – |
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
Kinetic Theory of Gases questions, year by year
The newest 40 show their opening words as they appeared in the official paper; older ones name the idea they tested. Open one for its options and the official answer.
JEE Main 20262 questions in 2 shifts
- 4 Apr, Shift 2Q33Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: If the average kinetic…
Idea: Kinetic Energy and Temp
Asked the year beforeEasyAssertion–reason - 5 Apr, Shift 1Q32Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Statement I: Change in internal…
Idea: Gamma and Degrees of Freedom
Asked the year beforeMediumTwo statements
JEE Main 20254 questions in 4 shifts
- 2 Apr, Shift 1Q48is the specific heat ratio of monoatomic gas A having 3 translational degrees of freedom. is the specific heat ratio…
Idea: Specific Heat Ratio Formula
New ideaMediumNumerical value - 2 Apr, Shift 2Q50The internal energy of air in sized room at 1 atmospheric pressure will be…
Idea: Law of Equipartition
Asked the year beforeEasyNumerical value - 7 Apr, Shift 1Q33Match the LIST-I with LIST-I LIST-I | LIST-II A. Triatomic rigid gas | I. B. Diatomic non-rigid gas | II.…
Idea: Gamma and Degrees of Freedom
MediumMatch the list - 7 Apr, Shift 2Q33The helium and argon are put in the flask at the same room temperature (300 K). The ratio of average kinetic energies (per molecule) of…
Idea: Kinetic Energy and Temp
Asked the year beforeEasySingle correct
JEE Main 202416 questions in 16 shifts
- 4 Apr, Shift 2Q40The translational degrees of freedom () and rotational degrees of freedom () of molecule are:
Idea: Degrees of Freedom
Asked the year beforeEasySingle correct - 5 Apr, Shift 1Q39If the collision frequency of hydrogen molecules in a closed chamber at is , then the collision frequency of the…
Idea: Collision Frequency
Asked the year beforeEasySingle correct - 5 Apr, Shift 2Q39If n is the number density and d is the diameter of the molecule, then the average distance covered by a molecule between two successive…
Idea: Mean Free Path
EasySingle correct - 6 Apr, Shift 1Q37A sample contains mixture of helium and oxygen gas. The ratio of root mean square speed of helium and oxygen in the sample, is :
Idea: Molecular Speed Ratios
Asked the year beforeEasySingle correct - 6 Apr, Shift 2Q41Energy of 10 non rigid diatomic molecules at temperature is :
Idea: Vibrational Degrees of Freedom
MediumSingle correct - 8 Apr, Shift 1Q39A mixture of one mole of monoatomic gas and one mole of a diatomic gas (rigid) are kept at room temperature (C). The ratio of…
Idea: Law of Equipartition
EasySingle correct - 8 Apr, Shift 2Q39Given below are two statements : Statement (I) : The mean free path of gas molecules is inversely proportional to square of molecular…
Idea: Mean Free Path
EasyTwo statements - 9 Apr, Shift 2Q41The temperature of a gas is C and the average translational kinetic energy of its molecules is K. The temperature at which the…
Idea: Kinetic Energy and Temp
Asked the year beforeEasySingle correct - 1 Feb, Shift 1Q39Two moles a monoatomic gas is mixed with six moles of a diatomic gas. The molar specific heat of the mixture at constant volume is :
Idea: Internal Energy of Gas Mixtures
Asked the year beforeEasySingle correct - 1 Feb, Shift 2Q39If the root mean square velocity of hydrogen molecule at a given temperature and pressure is 2 km/s, the root mean square velocity of…
Idea: Molecular Speed Ratios
Asked the year beforeEasySingle correct - 27 Jan, Shift 1Q39The average kinetic energy of a monoatomic molecule is 0.414 eV at temperature : (Use J/mol-K)
Idea: Kinetic Energy and Temp
Asked the year beforeEasySingle correct - 29 Jan, Shift 1Q39Two vessels A and B are of the same size and are at same temperature. A contains 1g of hydrogen and B contains 1g of oxygen. and…
Idea: Avogadro's Hypothesis Application
EasySingle correct - 30 Jan, Shift 1Q39At which temperature the r.m.s. velocity of a hydrogen molecule equal to that of an oxygen molecule at ?
Idea: Equating Speeds of Different Gases
New ideaEasySingle correct - 30 Jan, Shift 2Q39If three moles of monoatomic gas is mixed with two moles of a diatomic gas…
Idea: Adiabatic Exponent of Gas Mixtures
MediumSingle correct - 31 Jan, Shift 1Q39The parameter that remains the same for molecules of all gases at a given temperature is :
Idea: Kinetic Energy and Temp
Asked the year beforeEasySingle correct - 31 Jan, Shift 2Q39A gas mixture consists of 8 moles of argon and 6 moles of oxygen at temperature T. Neglecting all vibrational modes, the total internal…
Idea: Internal Energy of Gas Mixtures
Asked the year beforeEasySingle correct
JEE Main 202312 questions in 11 shifts
- 6 Apr, Shift 1Q45The number of air molecules per increased from to . The ratio of collision frequency of…
Idea: Collision Frequency
New ideaEasySingle correct - 6 Apr, Shift 1Q49Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Earth has atmosphere…
Idea: Planetary Atmosphere Retention
New ideaEasyAssertion–reason - 6 Apr, Shift 2Q39The temperature of an ideal gas is increased from 200 K to 800 K. If r.m.s. speed of gas at 200 K is . Then, r.m.s. speed of the gas…
Idea: Molecular Speed Types
Asked the year beforeEasySingle correct - 8 Apr, Shift 2Q33The temperature at which the kinetic energy of oxygen molecules becomes double than its value at C is
Idea: Kinetic Energy and Temp
Asked the year beforeEasySingle correct - 10 Apr, Shift 1Q32Match List I with List II : List I List II (A) 3 Translational degrees of freedom (I) Monoatomic gases (B) 3 Translational, 2 rotational…
Idea: Degrees of Freedom
Asked the year beforeEasyMatch the list - 10 Apr, Shift 2Q33A gas mixture consists of 2 moles of oxygen and 4 moles of neon at temperature T. Neglecting all vibrational modes, the total internal…
Idea: Internal Energy of Gas Mixtures
Asked the year beforeEasySingle correct - 11 Apr, Shift 1Q43Three vessels of equal volume contain gases at the same temperature and pressure. The first vessel contains neon (monoatomic), the second…
Idea: Molecular Speed Types
Asked the year beforeEasySingle correct - 11 Apr, Shift 2Q32The root mean square speed of molecules of nitrogen gas at is approximately : (Given mass of a nitrogen molecule =…
Idea: Molecular Speed Types
Asked the year beforeEasySingle correct - 12 Apr, Shift 1Q39If the r. m. s speed of chlorine molecule is 490 m/s at C, the r. m. s speed of argon molecules at the same temperature will be…
Idea: Molecular Speed Types
Asked the year beforeEasySingle correct - 13 Apr, Shift 1Q39The rms speed of oxygen molecule in a vessel at particular temperature is , where is the…
Idea: Molecular Speed Ratios
Asked the year beforeMediumSingle correct - 13 Apr, Shift 2Q39The mean free path of molecules of a certain gas at STP is , where is the diameter of the gas molecules. While maintaining the…
Idea: Mean Free Path Temperature Dependence
New ideaMediumSingle correct - 15 Apr, Shift 1Q32A flask contains Hydrogen and Argon in the ratio 2:1 by mass. The temperature of the mixture is 30°C. The ratio of average kinetic energy…
Idea: Kinetic Energy and Temp
Asked the year beforeEasySingle correct
JEE Main 202219 questions in 19 shifts
- 25 Jul, Shift 1Q38Following statements are given : (A) The average kinetic energy of a gas molecule decreases when the temperature is reduced. (B) The…
Idea: Kinetic Energy and Temp
Asked the year beforeEasyOther - 26 Jul, Shift 2Q42A gas has degrees of freedom. The ratio of specific heat of gas at constant volume to the specific heat of gas at constant pressure…
Idea: Gamma and Degrees of Freedom
Asked the year beforeEasySingle correct - 27 Jul, Shift 1Q39Same gas is filled in two vessels of the same volume at the same temperature. If the ratio of the number of molecules is 1:4, then A. The…
Idea: Molecular Speed Types
Asked the year beforeEasyOther - 27 Jul, Shift 2Q39Which statements are correct about degrees of freedom ? (A) A molecule with n degrees of freedom has n different ways of storing…
Idea: Degrees of Freedom
New ideaMediumOther - 28 Jul, Shift 1Q38Given below are two statements : Statement I : The average momentum of a molecule in a sample of an ideal gas depends on temperature.…
Idea: Molecular Speed Types
Asked the year beforeMediumTwo statements - 28 Jul, Shift 2Q8A vessel contains 14 g of nitrogen gas at a temperature of C. The amount of heat to be transferred to the gas to double the…
Idea: Molecular Speed Types
Asked the year beforeMediumSingle correct - 29 Jul, Shift 1 · Q54Internal Energy of Gas MixturesAsked the year beforeMedium
- 29 Jul, Shift 2 · Q49Molecular Speed TypesAsked the year beforeEasy
- 30 Jul, Shift 2 · Q8Molecular Speed TypesAsked the year beforeEasy
- 24 Jun, Shift 1 · Q51Molecular Speed TypesAsked the year beforeMedium
- 25 Jun, Shift 1 · Q37Molecular Speed RatiosAsked the year beforeEasy
- 25 Jun, Shift 2 · Q36Gamma and Degrees of FreedomAsked the year beforeEasy
- 26 Jun, Shift 1 · Q39Gamma and Degrees of FreedomAsked the year beforeMedium
- 26 Jun, Shift 2 · Q37Law of EquipartitionAsked the year beforeEasy
- 27 Jun, Shift 2 · Q38Mean Free PathAsked the year beforeMedium
- 28 Jun, Shift 1 · Q58Degrees of FreedomNew ideaEasy
- 28 Jun, Shift 2 · Q39Molecular Speed RatiosAsked the year beforeMedium
- 29 Jun, Shift 1 · Q42Van der Waals Pressure CorrectionNew ideaEasy
- 29 Jun, Shift 2 · Q43Avogadro's Hypothesis ApplicationNew ideaEasy
JEE Main 202118 questions in 16 shifts
- 4 Aug, Shift 1 · Q26Molecular Speed RatiosNew ideaEasy
- 26 Aug, Shift 1 · Q2Molecular Speed TypesNew ideaEasy
- 26 Aug, Shift 2 · Q16Microscopic Dalton's LawNew ideaEasy
- 27 Aug, Shift 2 · Q8Molecular Speed RatiosNew ideaEasy
- 24 Feb, Shift 2 · Q6Gas Pressure DerivationNew ideaEasy
- 24 Feb, Shift 2 · Q24Molecular Speed TypesNew ideaEasy
- 25 Feb, Shift 1 · Q21Kinetic Energy and TempAsked the year beforeMedium
- 25 Feb, Shift 2 · Q6Law of EquipartitionNew ideaMedium
- 26 Feb, Shift 1 · Q25Microscopic Dalton's LawNew ideaMedium
- 26 Feb, Shift 2 · Q13Law of EquipartitionNew ideaMedium
- 22 Jul, Shift 2 · Q5Kinetic Energy and TempAsked the year beforeEasy
- 25 Jul, Shift 2 · Q23Mean Free PathAsked the year beforeEasy
- 16 Mar, Shift 2 · Q7Mean Free PathAsked the year beforeEasy
- 17 Mar, Shift 1 · Q8Gamma and Degrees of FreedomAsked the year beforeMedium
- 17 Mar, Shift 1 · Q15Internal Energy of Gas MixturesAsked the year beforeMedium
- 17 Mar, Shift 2 · Q18Gamma and Degrees of FreedomAsked the year beforeMedium
- 18 Mar, Shift 1 · Q17Law of EquipartitionNew ideaEasy
- 18 Mar, Shift 2 · Q1Molecular Speed RatiosNew ideaEasy
JEE Main 202012 questions in 11 shifts
- 8 Jan, Shift 1 · Q9Relaxation TimeNew ideaMedium
- 8 Jan, Shift 2 · Q8Adiabatic Exponent of Gas MixturesNew ideaMedium
- 9 Jan, Shift 1 · Q8Vibrational Degrees of FreedomNew ideaEasy
- 9 Jan, Shift 2 · Q10Relaxation TimeNew ideaMedium
- 2 Sep, Shift 1 · Q9Internal Energy of Gas MixturesNew ideaEasy
- 2 Sep, Shift 2 · Q9Mean Free PathNew ideaMedium
- 3 Sep, Shift 1 · Q8Linear vs Non-Linear Polyatomic DOFNew ideaEasy
- 3 Sep, Shift 2 · Q8Gamma and Degrees of FreedomNew ideaMedium
- 4 Sep, Shift 1 · Q8Gamma and Degrees of FreedomNew ideaEasy
- 4 Sep, Shift 1 · Q23Internal Energy of Gas MixturesNew ideaEasy
- 5 Sep, Shift 1 · Q9Kinetic Energy and TempNew ideaMedium
- 6 Sep, Shift 2 · Q9Relaxation TimeNew ideaMedium
JEE Main 20171 question in 1 shift
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.
More topics in Kinetic Theory
This is the only topic tagged in this chapter.