Q. The most probable velocity (in cm/s) of hydrogen molecule at $27℃,$ will be
A) $19.3 \times 10^{4}$
B) $17.8 \times 10^{4}$
C) $24.93 \times 10^{9}$
D) $17.8 \times 10^{8}$
Explanation
(b)
Most probable velocity $= \sqrt{\frac{8RT}{\pi M}}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ T = (27 + 273) = 300\ K$
Molecular mass of $\ \ \ H_{2} = 2\ g\ mol^{- 1}$
Most probable velocity $\left( H_{2} \right)$
$= \sqrt{\frac{8 \times 8.314 \times 10^{7} \times 300}{3.14 \times 2}}$
$= 17.8 \times 10^{4}\ cm/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.