Question

The average translational kinetic energy of air molecules is $0.040eV$ ($1eV=1.6\times {10}^{-19}J$). Calculate the temperature of the air. Boltzman's constant $k=1.38\times {10}^{-23}J{K}^{-1}$

Answer 1

Given

the average translational $KE=0.040eV$

$=6.4\times {10}^{-21}J$

$\begin{array}{c}k=1.38\times {10}^{-23}J{k}^{-1}\\ T=?\end{array}$

the average translational kinetic energy

$\begin{array}{c}KE=\frac{3}{2}\times K\times T\\ 6.4\times {10}^{-21}=\frac{3}{2}\times 1.38\times {10}^{-23}\times T\\ T={309.1}^{\circ }C\end{array}$