What is potential barrier in a junction diode?

What do you mean by ‘biasing’ of a junction diode? Give its types.

Draw a circuit diagram of a forward-biased $p$-$n$ junction.

Draw a circuit diagram of a $p$-$n$ junction under reverse bias, using proper symbol for diode (not rectangular block).

Draw $V$-$I$ characteristic curve for a $p$-$n$ junction diode. Show the Zener voltage on the curve.

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