A Si bar is 0.25 cm long and 500 ?m2 in cross-sectional area. It is grounded at x=0 and biased at +20V at x=0.25 cm. Find the resistance and the current at 300K (a) when the Si bar is doped with 2×1017 cm-3 arsenic and (b) when the Si bar is doped both with 2×1017 cm-3 gallium and 1×1017 arsenic. (c) How long does it take for an average hole to drift through the bar in both cases?