Easy MCQ +4 / -1 PYQ · JEE Mains 2021

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 32g/mol; R = 8.3 J K$-$1 mol$-$1)

  1. A $\sqrt {{{3\pi } \over 8}}$ Correct answer
  2. B $\sqrt {{3 \over 3}}$
  3. C $\sqrt {{8 \over 3}}$
  4. D $\sqrt {{{8\pi } \over 3}}$

Solution

${V_{rms}} = \sqrt {{{3RT} \over M}}$<br><br>${V_{avg}} = \sqrt {{8 \over \pi }{{RT} \over M}}$<br><br>${{{V_{rms}}} \over {{V_{avg}}}} = \sqrt {{{3\pi } \over 8}}$

About this question

Subject: Physics · Chapter: Thermodynamics · Topic: Zeroth and First Law

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