Q. The average kinetic energy of a gas at $- 23℃$ and $75\ cm$ pressure is $5 \times 10^{- 14}erg$ for $H_{2}$. The mean kinetic energy of the $O_{2}$ at $227℃$ and $150\ cm$ pressure will be
A) $80 \times 10^{- 14}erg$
B) $20 \times 10^{- 14}erg$
C) $40 \times 10^{- 14}erg$
D) $10 \times 10^{- 14}erg$
Explanation
(d) Average kinetic energy
$E = \frac{3}{2}kT \Rightarrow \frac{E_{1}}{E_{2}} = \frac{T_{1}}{T_{2}} = \frac{(273 - 23)}{(273 + 227)} = \frac{250}{500} = \frac{1}{2}$
$\Rightarrow E_{2} = 2E_{1} = 2 \times 5 \times 10^{- 14} = 10 \times 10^{- 14}erg$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.