Question

The average kinetic energy of helium atom at $30{}^{\circ }C$ will be

• A. 13.6 eV
• B. 59.60 eV
• C. 15 keV
• D. less from 1 eV

Answer 1

Answer: (D)

The average kinetic energy of molecules of gas at temperature T
$E=\frac{3}{2}kT$
where k = Boltzmann constant
$=1.38\times {10}^{-23}J/K$
For helium gas $T=30+273=303K$
$\therefore$ $E_{He}=\frac{3}{2}\times 1.38\times {10}^{-23}\times 303$
$=6.27\times {10}^{-21}J$
$=\frac{6.27\times {10}^{-21}}{1.6\times {10}^{-19}}eV$
$=3.9\times {10}^{-2}eV$
$=0.039eV$
The average kinetic energy of helium atom is less than 1 eV.