The electron volt (eV) is a unit of energy commonly used in physics and particle physics, especially when discussing the energies of subatomic particles or the interactions within atoms and molecules. Scientists use the electron volt as a convenient unit for describing particle energies at the atomic or subatomic level, as energies in this realm are often relatively small in joules. For instance, the binding energies of electrons in atoms, the energies associated with atomic transitions, or the rest energies of subatomic particles like protons, neutrons, and electrons are commonly expressed in electron volts. The electron volt simplifies calculations and discussions in particle physics, quantum mechanics, and other fields dealing with energies on a microscopic scale.