JEE Main 2020 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 5 September 2020, Shift 1, Physics Q9

Question 9 of 75 in this shift, Physics question 9 of 25.

Number of molecules in a volume of 4 cm

^3

of a perfect monoatomic gas at some temperature T and at a pressure of 2 cm of mercury is close to ? (Given, mean kinetic energy of a molecule (at T) is

4\times10^{-14}

erg, g = 980 cm/s

^2

, density of mercury = 13.6 g/cm

^3

)

(1) $5.8\times10^{16}$
(2) $4.0\times10^{16}$
(3) $5.8\times10^{18}$
(4) $4.0\times10^{18}$ Official answer

Official answer

Option 4

NTA final key (Sep 2020).

Chapter: Kinetic Theory
Topic: Kinetic Theory of Gases
Idea tested: Kinetic Energy and Temp

Same idea in other shifts

Asked 11× in all

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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.