Problem $1.$ Initially at equilibrium, a uniformly doped Si wafer is struck by a mysterious ray that wipes out all minority carriers at t $0.$ Majority carriers are unaffected. Wafer doping is NA $1016$ cm$3,$ T $106$ s$,$ T $300$ K$.($a$)$ What is An at t $=0*?($b$)$ Which mechanism is dominant at t $0,$ generation or recombination? $($c$)$ Are low$-$level injection conditions satisfied inside the wafer at t$0?($d$)$ Derive Anp$()$ for t $>0$