What is the ratio of v_rms : v_avg : v_mp for gas molecules?

v_rms : v_avg : v_mp = √3 : √(8/π) : √2 ≈ 1.73 : 1.60 : 1.41. So v_rms > v_avg > v_mp. This relation is a direct JEE question type.

How many degrees of freedom do different gas molecules have?

Monatomic gas (He, Ar): f=3. Diatomic gas (H₂, N₂, O₂) at normal temperature: f=5. Triatomic/polyatomic: f=6. γ = (f+2)/f, so monatomic γ=5/3, diatomic γ=7/5. These are tested directly.

⚡Physics • Chapter Revision

Kinetic Theory of Gases Revision Notes

Quick facts, formula checklists, and concept reminders for JEE Main preparation.

3–5%

Weightage

~1 Q

Avg Qs

Easy

Difficulty

Syllabus Guidelines

Equation of state of a perfect gas

Work done on compressing a gas

Kinetic theory: assumptions, concept of pressure

Kinetic interpretation of temperature

RMS speed of gas molecules

Degrees of freedom, law of equipartition of energy

Applications to specific heat capacities of gases

Mean free path, Avogadro's number

Study Strategy & Guidelines

For JEE Main, Kinetic Theory of Gases is classified as a Easy difficulty chapter. It accounts for approximately 3–5% of the overall subject syllabus marks.

Read the corresponding NCERT chapter sections closely before attempting full mock tests.
Maintain a handwritten error-log book for calculation mistakes during chapter tests.
Verify all boundary conditions and assumptions for formulas under this topic.