A hollow copper sphere & a hollow copper cube of same surface area & negligible thickness , are filled with warm water of same temperature and placed in an enclosure of constant temperature a few degrees below that of the bodies. Then in the beginning:-

Options

A. Energy lost by the sphere is less than that by the cube
B. Energy lost by the sphereis more than that by the cube
C. Energy lost by the two are equal
D. Fall of temperature for sphere is less than that for the cube

Answer

C, D

Explanation

In this case as the surface areas of the two cases are same, the mass of water is different so for sphere the mass is less then that of cube. As temperatures are equal the radiation rate of both will be same but for sphere due to less heat capacity it will cool faster.