E-Field and Voltage Units

Units
for electric potential and fields

Previously,
we noted that electric forces are in Newtons (N),
electric potential energies are in Joules (J),
and charge is measured in Coulombs (C). Since
electric fields and potentials are obtained by dividing
the force and potential energy, respectively, by the
charge they are measured in units of (N/C) and (J/C)
respectively. But a “Joule per Coulomb” is also
known as a volt (V), and the electric potential
can also be referred to as the voltage. The Electric
field can also be noted in units of volts per meter (V/m).

Units

Electric field

V/m

N/C

Electric potential

V

J/C

Force

CV/m

N

Potential Energy

CV

J

A
convenient unit of electric potential energy is the
electron volt (eV). One electron volt is the
potential energy change of moving one electron’s worth of
charge, e, through one volt. One electron volt
equals 1.602E-19 (J). This unit is a convenient
for describing microscopic physics, such as the energy of
an electron in an atom. Related units are keV, MeV,
GeV, and TeV, which represent 103,
106, 109, and 1012 eV.
These units will be used in nuclear and particle physics
later in the semester.

Examples     Electric
fields index