In LED, light is emitted because of of charge carrier takes place.

The forward characteristic curve of a junction diode is shown in the figure :

Calculate the resistance of the diode at

(i) $V=0·5 V$

(ii) $I=60 mA$

What is the advantage of an LED bulb over filament bulb?

Draw circuit diagram for a $\mathrm{P}-\mathrm{N}$ junction to obtain reverse bias characteristic curves. Explain the phenomenon of reverse breakdown for a $\mathrm{P}-\mathrm{N}$ junction in reverse bias state by following process-

$\left(\mathrm{ii}\right)$ Zener breakdown

LED emits light when connected in _____.

(Fill in the blank using 'forward bias' or 'reverse bias')

In a semiconductor diode, what is meant by a potential barrier?

Draw a labelled diagram of a Zener diode as a voltage regulator.

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