A slab of white pine, 4 cm thick, has a moisture content of23 wt% at the start of the drying process. The equilibrium moisturecontent is 4 wt% for the humidity conditions in the drying air. The endsand edges are covered with moisture-resistance coating to preventevaporation. The diffusivity of water through pine is 1.0e-9 m2/s. If thetwo large surfaces are exposed to the drying air and the resistance tomass transfer outside the pine is negligible, (a) estimate the timerequired to reduce the moisture content of the slab at the center to 10wt% and (b) the time to reduce the (average) water content to 10 wt%. Ifthe external mass transfer resistance is equal to the internal masstransfer resistance, (c) estimate the time required to reduce themoisture content of the slab at the center to 10 wt% and (d) the time toreduce the (average) water content to 10 wt%.