$A$ Zener diode is used for

In the given circuit,the current through the Zener diode is.....$mA$.

In the circuit given,the current through the Zener diode is ....... $mA$.

For the circuit shown below,calculate the value of ${I}_{{z}}$ : (In ${mA}$)

$A$ Zener diode with a power rating of $1 \, W$ is to be used as a voltage regulator. If the Zener diode has a breakdown voltage of $5 \, V$ and it has to regulate an input voltage that fluctuates between $3 \, V$ and $7 \, V$,what should be the value of the series resistance $R_s$ for safe operation? (See figure)

The value of the resistor,$R_S$,needed in the $dc$ voltage regulator circuit shown here,equals