It is desired to dry a product whose shape is cubic 20 mm and 20 mm in length by using a stream of air flowing over it. The equilibrium humidity with the drying air is 2.5% wet base. After 9 hours of drying the moisture content has decreased from 40% to 9% wet basis, assume that the convective coefficient of mass transfer is large enough for the relative resistance to be zero. Determine: a. effective diffusivity. b. The moisture content of the sample when all faces are exposed to the