1. Two rods one made of copper and other made of steel of same length and same cross-sectional area are joined together. The thermal conductivity of copper and steel are \(385\, J s^{−1} K^{−1} m^{−1}\) and \(50\, Js^{−1} K^{−1} m^{−1}\) respectively. The free ends of copper and steel are held at \(100^\circ C\) and \(0^\circ C\) respectively. The temperature at the junction is, nearly: