Rods of copper, brass, and steel are welded together to form a Y-shaped figure. The cross-sectional area of each rod is 2 cm². The end of the copper rod is maintained at 100 °C and the ends of the brass and steel rods at 0 °C. Assume there is no heat loss from the surfaces of the rods. The lengths of the rods are: copper, 46 cm; brass, 13 cm; steel, 12 cm.
a) What is the temperature of the junction point?
b) What is the heat current in the copper rod?