A part made from steel case is carburized such that a suitable distribution of carbon is obtained in 8 hrs at 800C. If it is desired to obtain the same case in one half the time. What temperature should be used? [ Do=0.2X10^-4 m²/s; Q = 34000cal/mol; Gas constant (R) =8.314 J/mol-K ; x=diffusion distance is same in both cases]