A uniform steel rod has length l at 0^_ºC. Now one of its end is kept in ice (0^_ºC) and the other end is kept in steam (100^_ºC). If the coefficient of thermal expansion of the rod is α, how much is the thermal expansion of the rod at steady state?

At steady state, temperature becomes constant because heat flow through the tube is equal to as lost through the surfaces. As the temperatures 0 and 100 are given constant, there must be some data for its surface for steady state to be achieved.