The ends of two rods P and Q are kept at temperatures θ1oC and θ2oC .Rod P has radius r, length l and coefficient of thermal conductivity k. Rod Q has radius r/2 length l/2 and thermal conductivity 2k. Lateral surfaces of the rods are covered by insulating material. Rate of conduction of heat conduction through the rods P and Q are QP and QQ respectively, then