The base of a 2 cm X 3 cm X 20 cm long rectangular rod is kept at 175 degrees Celsius by electrically generated heat. This is known as a straight fin or longitudinal fin. The ambient air surrounding this fin is at 28 degrees Celsius and h=10 W/m^2-C. There is negligible heat loss at the tip of the rod.
1. What is the temperature 7 cm from the base if the rod is made of a) pure zinc b) lead c) pure gold. Which will be the hottest at this point?
2. What energy input is needed to keep the base temperature at the 175 degrees for each metal?