Consider a piece of steel undergoing a decarburization process at 925°C. The mass diffusivity of carbon in steel at 925°C is 1 × 10^-7 cm²/s. Determine the depth below the surface of the steel at which the concentration of carbon is reduced to 40% from its initial value as a result of the decarburization process for

(a) An hour

(b) Ten hours. Assume the concentration of carbon at the surface is zero throughout the decarburization process.