Electron-volt is a unit of ______.

The correct answer is option 1. energy.

Electron-volt (eV) is a unit of Energy.

Electron-volt (eV) is a unit of energy commonly used in atomic and particle physics. It represents the amount of kinetic energy gained or lost by an electron when it moves through an electric potential difference of one volt. One electron-volt is equal to approximately \(1.602 \times 10^{-19}\) joules.