A silicon p-n-p transistor has impurity concentrations of 5*10^18, 2*10^17, and 10^16 cm^-3 in the emitter, base, and collector, respectively. The base width is 1.0 um and the device cross-section area is 0.2 mm^2. When the emitter-base junction is forward biased to 0.5 V and the base-collector junction is reverse biased to 5V, calculate:
(a) The neutral base width
(b) The minority carrier concentration at the emitter-base junction