A ring sample of iron has a mean diameter of 5.5 cm and a cross-sectional area of 1.2 cm2 . It is wound with a uniformly distributed winding of 250 turns. The ring is initially demagnetized, and then a current of 1.5 ampere is passed through the winding. A flux meter connected to a secondary winding on the ring measures a flux change of 8.25 1023 weber. 

a. What magnetic field is acting on the material of the ring?

b. What is the magnetization of the ring material? 

c. What is the relative permeability of the ring material in this field?