3. Two horizontal uniform solids with length L and width of h are placed as shown in the figure below. The diffusivity of solute A in solid B is twice of that in solid C. The concentration of A at the bottom surface is zero, while the A concentration of A at the top surface of the upper solid is Cah. At steady-state condition, a) Show that the flux is constant through B and C b) Find the equation for the flux c) Find the concentration profiles in B and C d) Explain your results in terms of driving forces and resistances e) Calculate the average concentration of A in B and C h N Solid B h Solid C L