Mention the use of zener diode. 

Why is there a sudden increase in current in Zener diode ?

A zener diode is specified as having a breakdown voltage of $9.1 \;V$, with a maximum power dissipation of $364 \;mW$. What is the maximum current ($mA$) the diode can handle?

In a Zener regulated power supply a Zener diode with $V_{z}=6.0\; V$ is used for regulation. The load current is to be $4.0 \;mA$ and the unregulated input is $10.0\; V$. What should be the value of series resistor $R_{S} ?$

A zener diode of power rating $1.6\,W$ is to be used as voltage regulator. If the zener diode has a breakdown of $8\,V$ and it has to regulate voltage fluctuating between $3\,V$ and $10 \,V$. The value of resistance $R_5$ for safe operation of diode will be $………\Omega$