In a certain metal works, an iron bar is welded end to end to a 50-cm long copper bar of the same diameter. The free end of iron bar is kept at 0‘C while the free end of copper bar is at 100‘C. How long is the iron bar if the temperature of the junction point is 50‘C when the system reaches a steady state?
Q/t λ A ΔT/ d ΔT, Q/t and A are the same for both iron and cooper The ratio of λ of iron to the λ of copper is 80/385 0.21 λi / length of iron λc / length of copper length of iron 0.21*50 cm 10.5 cm .
