Before revision: The capacitance can then be solved by substitution, and the inductance is taken from Ampere's Law for two concentric conductors (coaxial wire) and with the definition of inductance , and where is magnetic induction, is the magnetic permeability of the dielectric, is the magnetic flux and is the infinitesimal vector area of the differential surface .
After revision: The capacitance can then be solved by substitution, The inductance is derived using the magnetic field due to the current in the wire (which can be determined with Ampère's law) and the definition of inductance : and where is magnetic induction, is the magnetic permeability of the dielectric, is the magnetic flux and is the infinitesimal vector area of the differential surface .