JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 17 March 2021, Shift 2, Physics Q18

Question 18 of 90 in this shift, Physics question 18 of 30, Section A.

If one mole of the polyatomic gas is having two vibrational modes and

\beta

is the ratio of molar specific heats for polyatomic gas

\left(\beta=\frac{\mathrm{C_P}}{\mathrm{C_V}}\right)

then the value of

\beta

is :

(1) $1.25$
(2) $1.2$ Official answer
(3) $1.35$
(4) $1.02$

Official answer

Option 2

NTA final key.

Chapter: Kinetic Theory
Topic: Kinetic Theory of Gases
Idea tested: Gamma and Degrees of Freedom

Same idea in other shifts

Asked 9× in all

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26 Jun 2022, Shift 1 · Q39A thermally insulated vessel contains an ideal gas of molecular mass M and ratio of specific heats 1.4. Vessel is moving with speed $v$ …MediumSingle correct
17 Mar 2021, Shift 1 · Q8A polyatomic ideal gas has 24 vibrational modes. What is the value of $\gamma$ ?MediumSingle correct
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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.