An electronvolt is a unit of energy commonly used to measure the energy carried by electromagnetic radiation.

- Electronvolts can be used for measurements at the scale of elementary particles as small as single photons, the quantum of the electromagnetic field.
- One electronvolt is the amount of energy that a single electron has when it is accelerated by a potential difference of 1 volt.
- If there is a difference in voltage of 1 volt between two points in an electrical circuit (within a capacitor for example) then the force required (and the energy gained) by a photon accelerating from one point to the other is 1 electronvolt.
- The electronvolt is not an SI unit of measurement.
- The joule, which is an SI unit of measurement, is too big to use at the level of particle physics.
- 1,000,000,000,000,000,000 eV = 0.1602176565 joule.
- The electronvolt is commonly used with metric prefixes.

https://en.wikipedia.org/wiki/Electronvolt>