The JEE Main Physics section requires speed and accuracy, along with a thorough understanding of the Kinetic molecular theory of gases. This article provides a set of JEE Main PYQs on Kinetic molecular theory of gases to help you understand the topic and improve your problem-solving skills with the help of detailed solutions by ensuring conceptual clarity, which will help you in the JEE Main 2026 preparation.
Whether you're revising the basics or testing your knowledge, these JEE Main PYQs will serve as a valuable practice resource.
The JEE Main 2026 exam is likely to continue on the same pattern as JEE Main 2025. Out of 90 questions, students can expect a fair mix from all three subjects. To get an edge, going through JEE Main previous year questions (PYQs) is one of the best strategies.
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JEE Main PYQs on Kinetic Molecular Theory of Gases
1.
Find net kinetic energy (maximum possible) associated with 20 diatomic molecules (Here kB is Boltzmann constant and T is absolute temperature of diatomic gas).- 35 kB T
- 70 kB T
- 60 kB T
- 30 kB T
2.
What will be the effect on the root mean square velocity of oxygen molecules if the temperature is doubled and oxygen molecule dissociates into atomic oxygen?- The velocity of atomic oxygen remains same
- The velocity of atomic oxygen doubles
- The velocity of atomic oxygen becomes half
- The velocity of atomic oxygen becomes four times
3.
At \(300 K\) the rms speed of oxygen molecules is \(\sqrt {\frac {\alpha+5}{\alpha}}\) times to that of its average speed in the gas. Then, the value of \(\alpha\) will be
(used \(\pi=\frac {22}{7}\))- 28
- 24
- 32
- 27
4.
The root mean square speed of molecules of nitrogen gas at 27°C is approximately : (Given mass of a nitrogen molecule = \(4.6 × 10^{–26}\) kg and take Boltzmann constant KB = \(1.4 × 10^{–23}\) JK–1 )- 1260 m/s
- 91 m/s
- 27.4 m/s
- 523 m/s
5.
What will be the effect on the root mean square velocity of oxygen molecules if the temperature is doubled and oxygen molecule dissociates into atomic oxygen?- The velocity of atomic oxygen remains same
- The velocity of atomic oxygen doubles
- The velocity of atomic oxygen becomes half
- The velocity of atomic oxygen becomes four times
6.
The mean free path of molecules of a certain gas at STP is 1500d, where d is the diameter of the gas molecules. While maintaining the standard pressure, the mean free path of the molecules at 373K is approximately- 1500d
- 750d
- 2049d
- 1098d
7.
Which statements are correct about degrees of freedom?
(A) A molecule with n degrees of freedom has n2 different ways of storing energy.
(B) Each degree of freedom is associated with (1/2)RT average energy per mole.
(C) A monatomic gas molecule has 1 rotational degree of freedom whereas diatomic molecule has 2 rotational degrees of freedom.
(D) CH4 has a total of 6 degrees of freedom.
Choose the correct answer from the option given below:- (B) and (C) only
- (B) and (D) only
- (A) and (B) only
- (C) and (D) only
8.
The number of air molecules per cm3 increased from 3 × 1019 to 12 × 1019. The ratio of collision frequency of air molecules before and after the increase in the number respectively is :- 0.25
- 0.75
- 1.25
- 0.50
9.
The ratio of speed of sound in hydrogen gas to the speed of sound in oxygen gas at the same temperature is:- 4 : 1
- 1 : 2
- 1 : 1
- 1 : 4
10.
The number density of molecules of a gas depends on their distance r from the origin as, $n(r) = n_0e^{-\alpha r^4}$ Then the total number of molecules is proportional to :- $n_0 \alpha^{1/4}$
- $n_0 \alpha^{-3}$
- $n_0 \alpha^{-3/4}$
- $\sqrt{n_0} \alpha^{1/2}$
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