A coil having 1000 turns is wrapped on ferromagnetic core constructed of sheet steel. The core has a cross-sectional area of 0.0009 m^2 and an average flux path of 30.0 cm. The core also has a length of 2 mm. The flux density in the core and airgap is 0.9 T.
a) What is the permeability of the steel at 0.9 T?
b) What is the magnetic field intensity in the airgap?