A bar of copper of length 75cm and a bar of length 125cm are joined end to end. Both are of circular cross – section with diameters 2cm. The free ends of copper and steel are maintained at 1000c and 00c respectively. The surfaces of the bars are thermally insulated. What is the temperature of copper – steel junction? Thermal conductivity of copper = 9.2x10-2k cal |m|0c| and that of steel is 1.1x10-2 k cal|m|0c|?
l1 = lengths of copper bars AB
l2 = length of steel bars BC.
Θ1 = temperature of free ends A
Θ2 = temperature of free ends C.
Θ = temperature of copper – steel.
In steady state, the heat flowing per second through two bars is the same i.e H1= H2
