A toroid solenoid has a cross-sectional area of 0.460 cm2, a mean radius of 11.5 cm, and 1900 turns. The space inside the windings is filled with a ferromagnetic substance that has a relative permeability of 510.
A) Determine the inductance of the solenoid. (You can neglect the variation of the magnetic field across the cross section of the toroid.)
B) If the material is removed from inside the solenoid and replaced by air, estimate the inductance of the solenoid?