In forward bias and in reverse bias, respectively, the width of the depletion layer of a p-n junction
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → decreases; increases
The width of the depletion layer follows the height of the potential barrier across the junction.
In forward bias the applied voltage opposes the barrier, the barrier height falls to \( V_0 - V \), and the depletion layer becomes narrower.
In reverse bias the applied voltage adds to the barrier, the height rises to \( V_0 + V \), more charge is uncovered on each side, and the depletion layer becomes wider.
So the width decreases in forward bias and increases in reverse bias.
NCERT (2026-27):
p-n Junction Diode Under Forward Bias – “… As a result, the depletion layer width decreases and the barrier height is reduced [Fig. 14.13(b)].”
p-n Junction Diode Under Reverse Bias – “… As a result, the barrier height increases and the depletion region widens due to the change in the electric field.”