A long, rectangular copper bar of thickness L is maintained at a temperature T 0 at its lower surface throughout the bar. Suddenly an electric current is passed through the bar and its upper surface...

A long, rectangular copper bar of thickness L is maintained at a temperature T₀
at its lower surface throughout the bar. Suddenly an electric current is passed through the bar and its upper surface is exposed to an air stream at T_∞, with convection coefficient h, while its bottom surface continues to be maintained at T0. Obtain differential heat conduction equation and write initial and boundary conditions in order to obtain the temperature distribution as a function of position and time.