- Electronvolts can be used to measure the energy of elementary particles, including photons, which are the smallest units of electromagnetic radiation (quanta of the electromagnetic field).
- The electronvolt is not part of the SI unit system. The SI unit for energy is the joule (J). However, joules are too large for many particle-level interactions.
- 1 electronvolt (eV) is equivalent to approximately 1.602 x 10^-19 joules (J).
- The electronvolt is often used in conjunction with metric prefixes to represent energy values at different magnitudes.
- kiloelectronvolt (keV): 1 keV = 1,000 eV (used for energies of X-rays)
- megaelectronvolt (MeV): 1 MeV = 1,000,000 eV (used for energies of gamma rays and nuclear reactions)
- gigaelectronvolt (GeV): 1 GeV = 1,000,000,000 eV (used for energies of particles in particle accelerators)
- teraelectronvolt (TeV): 1 TeV = 1,000,000,000,000 eV (used for energies of very high-energy particles in cosmic rays)

###### References

- Electronvolts can be used to measure the energy of elementary particles, including photons, which are the smallest units of electromagnetic radiation (quanta of the electromagnetic field).
- One electronvolt is equal to the energy gained by a single electron when it is accelerated across a potential difference of 1 volt.
- Photons (quanta of light) travelling through this same potential difference would also gain 1 eV of energy.

- The electronvolt is not part of the SI unit system. The SI unit for energy is the joule (J). However, joules are too large for many particle-level interactions.
- 1 electronvolt (eV) is equivalent to approximately 1.602 x 10^-19 joules (J).