Physics - Heat & Thermo Question with Solution | TestHub

Recall the formula of root mean square speed, ${\mathrm{v}}_{RMS}=\sqrt{\frac{3RT}{M}}$, 

$\Rightarrow \frac{{\left(v_{RMS}\right)}_{{\mathrm{O}}_2}}{{\left({ v}_{RMS}\right)}_{{\mathrm{H}}_2}}=\sqrt{\frac{M_{{\mathrm{H}}_2}}{{ M}_{{\mathrm{O}}_2}}}=\sqrt{\frac{2}{32}}=\frac{1}{4}$

$\Rightarrow {\left(v_{\mathrm{RMS}}\right)}_{{\mathrm{H}}_2}=4{\left({ \mathrm{v}}_{\mathrm{RMS}}\right)}_{{\mathrm{O}}_2}=4\times 160=640 {\text{m s}}^{-1}$