1) Unit of energy 
In physics, the electron volt (symbol eV; also written electronvolt) is a unit of energy equal to approximately {val|1.6|e=-19} joule (symbol J). By definition, it is the amount of energy gained (or lost) by the charge of a single electron moved across an electric potential difference of one volt. Thus it is 1 volt (1 joule per coulomb, {val|fmt=c...
special unit of energy equal to the change in energy of an electron passing through a potential difference of 1 V in vacuum NOTE 1 - 1 eV = 1,602 18 x 10-19 J (approximately) NOTE 2 - This unit of energy is admitted for use along with SI units.a unit of energy equal to the kinetic energy acquired by an electron in passing through a potential difference of 1 volt in vacuum 1 eV = 1.60219 ? 10-19 J approximately