Q 11-12-022NEETJEE MainMedium
At what temperature will the rms speed of hydrogen molecules equal the rms speed of oxygen molecules at $320$ K?
Answer: (D) $20$ K
$v_{\text{rms}} \propto \sqrt{\dfrac{T}{M}}$. Equal speeds need $\dfrac{T_H}{2} = \dfrac{320}{32}$, so $T_H = 20$ K.
Solution by Sreeraj P, M.Sc Physics