67. A cubical box with porous walls containing an equal number of

O₂ and H₂ molecules is placed in a large evacuated chamber. The entire system is maintained at constant temperature T. The ratio of V_rms of O₂ molecules to that of the V_rms of H₂ molecules, found in the chamber outside the box after a short interval is

(a) 1/2√2                                             (b) 1/4

(c)  1/√2                                               (d) √2

Answer-b