Consider the following statements (A) and (B) and identify the correct answer.

(A) A zener diode is connected in reverse bias, when used as a voltage regulator.

(B) The potential barrier of p-n junction lies between 0.1 V to 0.3 V.

**Correct answer:** (A) is correct and (B) is incorrect.

Why statement (A) is correct:
A Zener diode is designed to operate in reverse‑bias mode. When the reverse voltage reaches the Zener breakdown voltage, the diode conducts a well‑defined voltage regardless of further increases in the applied reverse voltage. This property is exploited in voltage‑regulator circuits, where the Zener diode maintains a constant output voltage by clamping the reverse voltage at its breakdown value.

Why statement (B) is incorrect:
The built‑in potential (also called the potential barrier) of a p‑n junction depends on the semiconductor material. For silicon, the barrier is typically about 0.6 V to 0.7 V; for germanium, it is about 0.2 V to 0.3 V. The statement claims the barrier lies between 0.1 V and 0.3 V, which is too low for silicon and generally inaccurate for most common diodes. Therefore, the range given is not a correct description of the p‑n junction potential barrier.

Hence, (A) is true and (B) is false, matching the selected option.