The relative electrical state of an object. A
charged conductor, for example, has a higher
potential than the earth, whose potential is
taken by convention to be zero. An electric
cell (battery) has a potential in relation to
e.m.f. (electromotive force), which can make
current flow in an external circuit. The
difference in potential between two points -
the potential difference - is expressed in
volts; that is, a 12V battery has a potential
difference of 12 volts between its negative
and positive terminals.