If the forward bias voltage in a diode is increased, the width of the depletion region
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → decreases
In forward bias the applied voltage opposes the built-in barrier potential, so the effective barrier becomes \( V_0 - V \). Majority carriers are pushed towards the junction and neutralise some of the fixed ions at its edges, so the depletion region becomes narrower as the forward voltage is increased.
Note: A similar question was also asked in CUET (UG) 2023 on 07-06-2023 (Slot 3) and on 25-05-2023 (Slot 3).
NCERT (2026-27):
p-n Junction Diode Under Forward Bias – “When an external voltage V is applied across a semiconductor diode such that p-side is connected to the positive terminal of the battery and n-side to the negative terminal [Fig. 14.13(a)], it is said to be forward biased. … The direction of the applied voltage (V ) is opposite to the built-in potential V0. As a result, the depletion layer width decreases and the barrier height is reduced [Fig. 14.13(b)].”
