Define an electron Volt $(eV)$ and express its value in Joule $(J)$ units.

(N/A) An electron volt $(eV)$ is defined as the amount of kinetic energy gained or lost by a single electron accelerating from rest through an electric potential difference of $1 \ V$.
Mathematically,the energy $E$ is given by $E = qV$.
Here,the charge of an electron $q = 1.602 \times 10^{-19} \ C$ and the potential difference $V = 1 \ V$.
Therefore,$1 \ eV = (1.602 \times 10^{-19} \ C) \times (1 \ V) = 1.602 \times 10^{-19} \ J$.