of the magnetic field within the material, produced by a given current. [P4.2, P4.5]
of: a material medium
is: a property of the material that determines the magnitude of the magnetic field within the material, produced by a given current. [P4.2, P4.5]
appears, for example: in the equation for the magnitude of the magnetic field at a distance 
from a long steady electric current 
[P4.2]
is equal: to the permeability of free space 
times the relative permeability 
of the material.
is equal: in a vacuum, to the permeability of free space, [P4.2]
Copyright 1997, The Open University