ELECTRICAL POTENTIAL ENERGY
As we said, when a charge moves in an electric field, unless its displacement is
always perpendicular to the field, the electric force does work on the charge. If WE
is the work done by the electric force, then the change in the charge’s electrical
potential energy is defined by
The Power of a Word
Come test day, remember
that electric potential and
electric potential energy
are different things. The
former is measured in
joules per coulomb, while
the latter is measured
in joules.∆UE = −WE
Likewise, remember that
energy is the ability to do
work, not the doing
of work itself.Notice that this is the same equation that defined the change in the gravitational
potential energy of an object of mass m undergoing a displacement in a
gravitational field (∆UG = −WG).
- A positive charge +q moves from position A to position B in a
uniform electric field E.