$A$ Zener diode of breakdown voltage $20 \ V$ is connected as shown in the given circuit. The current through the Zener diode is (in $mA$)

$A$ Zener diode is to be used as a voltage regulator. Identify the correct setup.

$A$ Zener diode with $5\ V$ Zener voltage is used to regulate an unregulated $DC$ voltage input of $25\ V$. For a $400\ \Omega$ resistor connected in series, the Zener current is found to be $4$ times the load current. The load current $(I_L)$ and load resistance $(R_L)$ are:

In the given circuit,the value of current $I_{L}$ will be in $mA$. (When $R_{L} = 1 \, k\Omega$)

Find the current through the Zener diode in the given circuit. (in $mA$)

$A$ potential divider circuit is connected to a $DC$ source of $20 \,V$, a light emitting diode $(LED)$ with a glow-in voltage of $1.8 \,V$, and a Zener diode with a breakdown voltage of $3.2 \,V$. The total length $(PR)$ of the resistive wire is $20 \,cm$. The minimum length of $PQ$ required for the $LED$ to just glow is ............. $cm$.