A cylindrical rod of length l and cross - sectional radius r is placed at a distance of 50 r from a infrared point source S of power 1.25 kw as shown in the figure. The lateral surface of the rod is perfectly insulated from the surroundings . If the cross - section A absorbs 80 % of the incident energy and the temperature difference between the ends of the rod is constant , then the rate of heat flow through the rod in steady state is

Options

A. 0.2 J/s
B. 0.125 J/s
C. 0.1 J/S
D. 0.25 J/s

Answer

C