The average kinetic energy ($E$) of a monoatomic gas atom (like Helium) is given by the formula $E = \frac{3}{2} k_B T$. Given temperature $T = 30^\circ\text{C} = 30 + 273.15 = 303.15 \text{ K}$ . The Boltzmann constant $k_B \approx 1.38 \times 10^{-23} \text{ J K}^{-1}$ . Substituting the values: $E = \frac{3}{2} \times (1.38 \times 10^{-23} \text{ J K}^{-1}) \times 303.15 \text{ K} \approx 6.27 \times 10^{-21} \text{ J}$. To convert this energy into electron-volts (eV), we use the conversion factor $1 \text{ eV} = 1.602 \times 10^{-19} \text{ J}$ : $E_{\text{eV}} = \frac{6.27 \times 10^{-21}}{1.602 \times 10^{-19}} \approx 0.039 \text{ eV}$. This value is significantly less than 1 eV.