Electronvolt

This page or section needs to be cleaned up. Please help clean the page if you can. For tips on making this article better, read "How to edit a page" and "How to write Simple English pages". (November 2024)

The electron-volt or electron volt, symbol eV, is used to measure energy. It is defined as the amount of energy an electron gains after being accelerated by 1 volt of electricity. Joule is used often for energy measurement, while sometimes useful to use electron-volts for a tiny amount of energy, or quantum, such as that carried by a single subatomic particle.

To convert joules into electron-volts, divide joules by the charge of an electron, which is about 1.602×10⁻¹⁹ coulomb.

E.g. 5 J = 5/1.602×10⁻¹⁹
5 J = 3.121×10⁺¹⁹ eV.

The electronvolt is often used in atomic, nuclear and particle physics. For example, the energy of photons can be measured by the voltage necessary to overcome their photoelectric effect.