JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyRecall

JEE Main 18 March 2021, Shift 2, Physics Q1

Question 1 of 90 in this shift, Physics question 1 of 30, Section A.

Consider a sample of oxygen behaving like an ideal gas. At 300 K, the ratio of root mean square (rms) velocity to the average velocity of gas molecule would be : (Molecular weight of oxygen is 32 g/mol; R

=8.3

J K

^{-1}

mol

^{-1}

)

(1) $\sqrt{\frac{3\pi}{8}}$ Official answer
(2) $\sqrt{\frac{8\pi}{3}}$
(3) $\sqrt{\frac{8}{3}}$
(4) $\sqrt{\frac{3}{3}}$

Official answer

Option 1

NTA final key.

Chapter: Kinetic Theory
Topic: Kinetic Theory of Gases
Idea tested: Molecular Speed Ratios

Same idea in other shifts

Asked 8× in all

6 Apr 2024, Shift 1 · Q37A sample contains mixture of helium and oxygen gas. The ratio of root mean square speed of helium and oxygen in the sample, is :EasySingle correct
1 Feb 2024, Shift 2 · Q39If the root mean square velocity of hydrogen molecule at a given temperature and pressure is 2 km/s, the root mean square velocity of…EasySingle correct
13 Apr 2023, Shift 1 · Q39The rms speed of oxygen molecule in a vessel at particular temperature is $\left(1+\frac{5}{x}\right)^{\frac{1}{2}} v$ , where $v$ is the…MediumSingle correct
25 Jun 2022, Shift 1 · Q37The relation between root mean square speed ( $v_{rms}$ ) and most probable speed ( $v_p$ ) for the molar mass M of oxygen gas molecule at the…EasySingle correct
28 Jun 2022, Shift 2 · Q39What will be the effect on the root mean square velocity of oxygen molecules if the temperature is doubled and oxygen molecule dissociates…MediumSingle correct
4 Aug 2021, Shift 1 · Q26The ratio of average speed to the rms speed of oxygen molecule is $\sqrt{\frac{8}{x\pi}}$ . The value of ‘x’ is ________ .EasyNumerical value
27 Aug 2021, Shift 2 · Q8If the rms speed of oxygen molecules at $0^\circ\mathrm{C}$ is 160 m/s, find the rms speed of hydrogen molecules at $0^\circ\mathrm{C}$ .EasySingle correct

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.