question_answer

There are two rods of the same metal, same length, same area of cross-section, but one of square cross-section and the other of circular cross- section. One end of each is kept immersed in steam. After the steady state is reached, the other ends of the rods are touched. Which one will be hotter? Give reason.

Answer:

                The surface area of the rod of circular cross-section will be smaller, because for a given area a circle has least perimeter. So the loss of heat by radiation will be small. Hence the other end of the circular rod will be hotter than the other end of the square rod.