A diffusion process is run at 1200 ºC with the surface concentration of diffusing atoms kept constant at 1024 atoms/m3 . The process is run for 3 h. If there are no diffusing atoms at the start of the diffusion process inside the diffusing material, at what depth below the surface is the concentration of atoms 1022 atoms/m3 ? The diffusion coefficient at 1200ºC is 7.0 X 10-17 m2 /s.