| electronvolt | |
|---|---|
| Unit system | Non-SI accepted unit |
| Unit of | energy |
| Symbol | eV |
| Conversions | |
| 1 eV in ... | ... is equal to ... |
| joules (SI) | 1.602176634×10−19 J.[1] |
In physics, an electronvolt (symbol eV), also written electron-volt and electron volt, is the measure of an amount of kinetic energy gained by a single electron accelerating through an electric potential difference of one volt in vacuum. When used as a unit of energy, the numerical value of 1 eV in joules (symbol J) is equal to the numerical value of the charge of an electron in coulombs (symbol C). Under the 2019 revision of the SI, this sets 1 eV equal to the exact value 1.602176634×10−19 J.[1]
Historically, the electronvolt was devised as a standard unit of measure through its usefulness in electrostatic particle accelerator sciences, because a particle with electric charge q gains an energy E = qV after passing through a voltage of V.