Which of the following semi-conducting devices is used as a voltage regulator?

Choose the correct statement about $Zener$ diode.

$A$ $9\,V$ stabilized voltage supply is required to run a car stereo system from the car's $12\,V$ battery. $A$ Zener diode with $V_z = 9\,V$ and $P_{max} = 0.27\,W$ is to be used as the voltage regulator. The load resistance is $450\,\Omega$. The value of the series resistor $R_s$ is....$\Omega$.

In the given circuit, find the voltage drop $V_L$ across the load resistance $R_L$. (in $V$)

The figure represents a voltage regulator circuit using a Zener diode. The breakdown voltage of the Zener diode is $6\,V$ and the load resistance is $R_L = 4\,k\Omega.$ The series resistance of the circuit is $R_i = 1\,k\Omega.$ If the battery voltage $V_B$ varies from $8\,V$ to $16\,V,$ what are the minimum and maximum values of the current through the Zener diode?

In a Zener diode,