A given p-n junction is forward biased. Which of the following statem…

The correct answer is Option (3) → The height of potential barrier is decreased.

In forward bias the applied voltage opposes the built-in barrier potential, so the effective barrier height becomes \( V_0 - V \). The barrier is lowered and the depletion layer becomes narrower, letting majority carriers cross the junction.

Option (1) The electrons move from p-region to n-region. — Incorrect. Electrons are the majority carriers of the n-region; in forward bias they move from the n-region into the p-region.

Option (2) The height of potential barrier is increased. — Incorrect. The barrier height increases (to \( V_0 + V \)) in reverse bias, not in forward bias.

Option (3) The height of potential barrier is decreased. — Correct. The applied voltage opposes the barrier, so its height falls from \( V_0 \) to \( V_0 - V \).

Option (4) The width of depletion region increases. — Incorrect. The depletion region becomes narrower in forward bias; it widens in reverse bias.

NCERT (2026-27):
p-n Junction Diode Under Forward Bias – “… 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)]. The effective barrier height under forward bias is (V₀ – V).”