# Encyclopedia Magnetica

Encyclopedia of magnetics and electromagnetics.

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# Magnetic monopole

 Stan Zurek, Magnetic monopole, Encyclopedia-Magnetica.com, {accessed 2019-03-19}
Animation of field lines around a magnetic dipole and an electric dipole

by Geek3, CC-BY-SA-3.0

Magnetic monopole - a hypothetical entity proposed on the basis of theoretical calculations.

Gauss's law for magnetic field is often given in a differential form:

 $\nabla · B = 0$

where: ∇ denotes divergence, and $B$ is the magnetic flux density.

As a consequence of this equation there should be no “magnetic charge” or magnetic monopole, and all magnetic fields should be produced by magnetic dipoles.

However, Paul Dirac showed theoretically that the existence of magnetic monopoles would explain why the electric charge is quantised, which so far also remains unexplained.1)

The search for magnetic monopole continues and so far no evidence was found for its existence.