The Magnetic Constant or the Vacuum Permeability can be defined as the the value of magnetic permeability in a classical vacuum, represented by the symbol μ0. Permeability is measured as the ability of a meterial to form a magnetic field within itself. It is defined as the degree of magnetization or the amount of magnetization, a material obtains in response when a magnetic filed is applied on that material. The symbol of Magnetic permeability is μ. The opposite term for Magnetic Permeability is Magnetic Reluctivity.