One end of a solid cylindrical copper rod 0.200 m long is maintained at a temperature of 20.00 K The other end is blackened and exposed to thermal radiation from surrounding walls at 500.0 K the sides of the rod are insulated, so no energy is lost or gained except at the ends of the rod. When equilibrium is reached, what is the temperature of the blackened end? (Hint: Since copper is a very good conductor of heat at low temperature, with k = 1670 W/m· K at 20 K, the temperature of the blackened end is only slightly higher than 20.00 K)