Astronomers use electron volts to measure the energy of electromagnetic radiation, or photons, in the x-ray and gamma-ray wavebands of the electromagnetic spectrum, and also use electron volts to describe the difference in atomic or molecular energy states which give rise to ultraviolet, visual, or infrared lines, or ...

Why are electron volts used instead of joules?

You are probably familiar with using Joule as a measure of energy. In particle physics, however, we use something more convenient called electron volt (eV) instead. The reason we use this is that the energies we are measuring in particle collisions are very small and are related to the energies of single particles.

Why are electron volts more convenient?

Since energies at atomic level are very small and are expressed in electron volt rather than Joule because Joule is a bigger unit. Hence the unit electron volt for energy is more convenient than joule,when we are dealing with atoms and nuclei to express the energy.