Carbon is allowed to diffuse through a steel plate 10 mm thick.

Carbon is allowed to diffuse through a steel plate 10 mm thick. The concentrations of carbon at the two faces are 0.85 and 0.40 kg C/cm3 Fe, which are maintained constant. If the preexponential and activation energy are 6.2 × 10−7 m2/s and 80,000 J/mol, respectively, compute the temperature at which the diffusion flux is 6.3 × 10−10 kg/m2-s.