A thin sheet of Iron is in contact with a carburizing gas on one side and a decarburizing gas on the other at 1000C a. Sketch the resultant carbon concentration profile when a steady state has been reached assuming surface concentration are maintained at 0.15 and 1.4 wt% C b. If Dc increases from 2.5 x 10 -11 m2 s-1 at 0.15% C to 7.7 x 10 -11 m2 s-1 at 1.4%C, what will be the quantitative relationship between the concentration gradients at the surfaces