- This article is about the electromagnetic phenomenon. In
physics, there are two kinds of dipoles (from the Greek terms
di(s)-, meaning "two," and polos, meaning "pivot" or "hinge"):
An electric dipole and a magnetic dipole. An electric dipole
refers to an object or system in which positive and negative
electric charges are located at two separate points. The
simplest example is a pair of electric charges of equal
magnitude but opposite sign, separated by some small distance. A
permanent electric dipole is called an electret. A magnetic
dipole is an object or system in which opposite magnetic poles
(north and south) are separated by a distance. A magnetic dipole
is produced by a closed circuit of electric current. A simple
example of this is a single loop of wire with some constant
current flowing through it. A dipole can be characterized by its
dipole moment, a vector quantity. For the simple electric dipole
mentioned above, the electric dipole moment points from the
negative charge towards the positive cha