A silicon crystal having a cross-sectional area of 0.001 cm² and a length of 10-3 cm is connected at its ends to a 10-V battery. At T = 300 K, we want a current of 100 mA in the silicon. Calculate (a) the required resistance R, (b) the required conductivity. (c) the density of donor atoms to be added to achieve this conductivity, and (d) the concentration of acceptor atoms to be added to form a compensated p-type material with the conductivity given from part (b) if the initial concentration of donor atoms is Na = 1015 cm-3