The circuit shown below is working as an $8\; V\; dc$ regulated voltage source. When $12 \; V$ is used as input, the power dissipated (in $mW$) in each diode is (considering both zener diodes are identical).

$A$ Zener diode of breakdown voltage $V_{Z} = 8\,V$ and maximum Zener current $I_{ZM} = 10\,mA$ is subjected to an input voltage $V_{i} = 10\,V$ with a series resistance $R = 100\,\Omega$. In the given circuit,$R_{L}$ represents the variable load resistance. The ratio of the maximum and minimum value of $R_{L}$ is

The graph given below represents $I-V$ characteristics of a Zener diode. The part of the characteristics curve that is most relevant for its operation as a voltage regulator is

If the current in the Zener diode is five times the current in $R_1$ and the breakdown voltage of the diode is $6 \text{ V}$,find the value of $R$.

$A$ Zener diode is made by

$A$ reverse biased Zener diode when operated in the breakdown region works as