10. A silicon n'p junction is biased at VR = 5 V. (a) Determine the change in built-in potential barrier if the doping concentration in the p region increases by a factor of 3. (b) Determine the ratio of junction capacitance when the acceptor doping is 3N, compared to that when the acceptor doping is Na. (c) Why does the junction capacitance increase when the doping concentration increases?