Electric potential, measured in volt (V).

Diamagnetism is a form of magnetism that is only exhibited by a substance in the presence of an externally applied magnetic field. It is the result of changes in the orbital motion of electrons due to the application of an externally applied magnetic field. Applying a magnetic field causes a momentary electromotive force (a consequence of Faraday's law), which modifies the electronic orbitals of atoms/molecules in a substance in such a way, that the orbitals produce an induced magnetic field, which opposes the applied field (a consequence of Lenz's law). However, the induced magnetic moment is very small in most everyday materials.
Diamagnets are repelled by magnetic fields. However, since diamagnetism is such a weak property its effects are not observable in every-day life.
However, in Magnetic Resonance Imaging for example barium sulfate suspensions lead with its weak negative magnetic susceptibility to a decrease in signal.

See also magnetism, ferromagnetism, paramagnetism, and superparamagnetism.