A sheet of steel of thickness 0.50mm is tinplated on both sides and subjected to a corrosive environment. During service, the tinplate becomes scratched, so that steel is exposed over 0.5% of the area of the sheet. Under these conditions it is estimated that the current consumed at the tinned surface by the oxygen-reduction reaction is 2 X 18" A m-1. Will the sheet rust through within 5 years in the scratched condition? The density of steel is 7.87Mgm-3. Assume that the steel corrodes to give Fez+ ions. The atomic weight of iron is 55.9.