A hollow copper sphere S and a hollow copper cube C, both of negligible thin wall of same area, are filled with water at 90 C and allowed to cool in the same environment. The graph that correctly represents their cooling is

Dear student,

The rate of loss of heat depends upon the area of the cooling body, its material and the difference in its temperature and environment’s. Since all these pararmeters are same, the rate of heat loss is same.

Now,
and since mass and specific heat capacity of both cube and sphere is same, the rate of cooling is also same. So the correct answer is option C.