Problem 3 (5 points): A negligibly thin electrically conducting foil is sandwiched foil, between two plane walls of equivalent thickness L and thermal conductivity k. If an electric current is passed through the foil, heat is generated within the foil, creating a uniform heat flux at the interface between the walls. Consider L I k k " conditions for which the walls are initially at a uniform temperature T,. Heating from the foil maintains a net emitted heat flux q". at the interface for t > 0. Concurrently (f > 0), the exposed surfaces are maintained at a fixed temperature T, that exceeds T.. Neglect contact resistance between the walls and foil. (a) (3 points) On Tx coordinates, sketch the temperature distributions for the following conditions: initial condition (t