A charged particle located within the influence of an electric field experiences an interaction that is formally equivalent to other work by force fields in physics. The electric field performs work on the particle. The work per unit of charge is defined by moving a negligible test charge between two points, and is expressed as the difference in electric potential at those points. The work can be done, for example, by electrochemical devices (electrochemical cells) or different metals junctions generating an electromotive force. The physical and mathematical formalism for electrical work is identical to that of mechanical work.