A p-n junction diode is under reverse bias. At breakdown voltage, the…

The correct answer is Option (3) → increases abruptly

Under reverse bias only a tiny, almost constant reverse current (due to minority carriers) flows. When the reverse voltage reaches the breakdown voltage, the strong field at the junction frees a large number of carriers (Zener or avalanche breakdown), and the reverse current increases abruptly while the voltage stays nearly constant.

This sharp rise at an almost fixed voltage is used in the Zener diode as a voltage regulator.

NCERT (2026-27):
p-n Junction Diode under Reverse Bias – “… The current under reverse bias is essentially voltage independent upto a critical reverse bias voltage, known as breakdown voltage (\( V_{br} \)). When \( V = V_{br} \), the diode reverse current increases sharply. Even a slight increase in the bias voltage causes large change in the current.”