KVPY SB SX Exam 2011 Question Paper

Two rods, one made of copper and the other steel of the same length and cross sectional area are joined together. (The thermal conductivity of copper is $385{\mathrm{Js}}^{-1}{\mathit{m}}^{-1}{\mathit{K}}^{-1}$ and steel is $50{\mathrm{Js}}^{-1}{\mathit{m}}^{-1}{\mathit{K}}^{-1}$) If the copper end is held at 100 C and the steel end is held at 0 C, what is the junction temperature (assuming no other heat losses)?