Q 11-12-015NEETJEE MainMedium
For a gas at a given temperature, the ratio $v_{\text{rms}} : v_{\text{avg}} : v_{\text{mp}}$ is
Answer: (B) $\sqrt{3} : \sqrt{8/\pi} : \sqrt{2}$
Concept. $v_{\text{rms}} = \sqrt{\dfrac{3RT}{M}}$, $v_{\text{avg}} = \sqrt{\dfrac{8RT}{\pi M}}$, $v_{\text{mp}} = \sqrt{\dfrac{2RT}{M}}$.
Step 1. Ratio. $\sqrt3 : \sqrt{8/\pi} : \sqrt2$ (about $1.73 : 1.60 : 1.41$).
Answer. $\sqrt3 : \sqrt{8/\pi} : \sqrt2$ (Option B).
Solution by Sreeraj P, M.Sc Physics