PROBLEM FOUR ( 25 points): A drug patch is designed to slowly deliver a drug (species A) through the body tissue to an infected zone beneath the skin. The patch is implanted just below the skin. A diffusion barrier attached to the bottom surface of the patch keeps the surface concentration of the drug dissolved in the body tissue constant at 2mol/m3, which is below the solubility limit of the is 5mm. To be effective, The mean distance from the drug patch to the infected area of tissue when it reaches the infected zone. Determine the time it will take in hours for the drug to begin to be effective for treatment (at CA=0.2mol/m3 ). The effective molecular diffusion coefficient of the drug through the body tissue both healthy and infected is 1106cm2/s