A toroid is fille with liquid oxygen that has a magnetic susceptibility of 4*10^-3. The toroid has 2000 turns and carries a current of 15 A. Its mean radius is 20 cm, and the radius of its cross section is 8 mm. (a) What is the magnetization? (b) What is the magnetic feild? (c) What is the percentage change in magnetic feild produced by the liquid oxygen?