Broadcast on film.

There are two films made of the same material, of the same width and length, but of different thicknesses, L_z1 and L_z2. It is desired to know

(a) how different the molar flux will be in the films if the same concentration difference is maintained between the two sides of the film

(b) how different the concentration differences must be if the molar flux in both films is to be the same.