A Zener diode is used in a voltage regulator circuit as shown below. Its breakdown voltage is 15 V. What is the current flowing through the zener diode?

5 mA

The correct answer is Option (1) → 5 mA

Current through the diode is zero because it is reversed biased.

Now,

$V=IR$ [Ohm's law]

$⇒I=\frac{V}{R_{net}}=\frac{25}{(1000+500)}=5mA$