Draw the voltage‐current characteristic of a zener diode.

Why is the conductivity of a n-type semiconductor greater than that of p-type semiconductor even when both of these have same-level of doping?

If the emitter and base of $n-p-n$ transistor have the same doping concentration, explain how will the base and collector current be affected ?

Draw the circuit diagram of a half-wave rectifier using a $p$-$n$ junction diode.