A hollow sphere is constructed of aluminum with an inner diameter of 4 cm and an outer diameter of 8 cm. The inside temperature is 100 C and the outer temperature is 50 C. Suppose the sphere is covered with a 1-cm layer of an insulating material having k= .05 W/m C and the outside of the insulation is exposed to an enviroment with h= 20 W/m2 C and T∞ = 10 C. The inside of the sphere remains at 100 C. Calculate the heat transfer under these conditions.