A pipe 0.026 m in diameter and 0.22 m long can transfer 3476 J of heat per second with a temperature difference across the ends of 7?C. Compare this performance with the heat transfer of a solid silver bar of the same di- mensions by finding the ratio of the given heat to that of the silver bar. The thermal conduc- tivity of silver is 427 W/m · ? C. (Silver is the best heat conductor of all metals.)