The incorrect statement about the property of a Zener diode is

In a Zener diode,the reverse bias voltage is $3 \ V$ and the width of the depletion region is $300 \ \mathring{A}$. The electric field intensity will be $\dots \ V/cm$.

$A$ 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?

Consider the following statements $A$ and $B$ and identify the correct choice of the given answers.
Statement $A$: The potential barrier of a $PN$ junction lies between $0.1 \, V$ to $0.3 \, V$ approximately.
Statement $B$: $A$ Zener diode is always connected in reverse bias.

The Zener diode is used for

$A$ Zener diode having breakdown voltage $V_z = 6 \, V$ is used in a voltage regulator circuit as shown in the figure. The minimum current required to pass through the Zener to act as a voltage regulator is $10 \, mA$ and the maximum allowed current through the Zener is $40 \, mA$. The maximum value of $R_s$ for the Zener to act as a voltage regulator is (in $\Omega$)