Draw a circuit diagram for $p$-$n$ junction diode in forward bias. Sketch and discuss the voltage versus current graph for the same.

Draw a labelled circuit diagram of a half-wave rectifier and give its output wave-form.

Explain the use of a $p$-$n$ junction diode as a rectifier. Draw the circuit diagram of a full-wave rectifier and explain its working. Draw the input and output wave-forms.

Show by drawing labelled diagrams, the nature of output voltages in case of a half-wave rectifier.

Draw a neatly labelled circuit diagram of a full-wave rectifier using two junction diodes.

With reference to semiconductor devices, define a $p$-type semiconductor and a Zener diode. What is the use of Zener diode?

What is LED? Explain how radiations are given out by LED?