permeability (μ) Also called magnetic permeability (symbol μ), the ratio of the magnetic flux density, B, in a substance to the external magnetic field strength, H, i.e.: The permeability of free space, μ0 is also called the magnetic constant and has the value 4π × 10-7 H m-1 in SI units. The relative permeability of a substance, μr, is given by μ / μ0, and is therefore dimensionless. Materials showing diamagnetism and paramagnetism have permeabilities just below free space value; materials showing ferromagmetism have permabilities a thousand times greater. Related category • ELECTRICITY AND MAGNETISM Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |