A slab, extending from x $=0$ to x $=$ L and of infinite extent in the y and z directions, is initially at a uniform temperature Ti $.$ For times t $0,$ a constant heat flux qw$,$ is applied to the surface at x $=$ L$,$ while the surface at x $=0$ is kept perfectly insulated. Assume that the thermophysical properties of the slab are constant. Obtain an expression for the unsteady$-$state temperature distribution T$($x$,$ t$)$ in the slab for t $>0.$