There are two spherical balls A and B of the same material with same surface ,but the diameter of A is half that of B.If A and B are heated to the same temperature and then allowed to cool ,then

Rate of heat transfer by radiation = A x T4 Temperature is same for both spheres A = Surface area Surface area of sphere = π d2 Cooling rate of big sphere / Cooling rate of small sphere = d2 big / d2small