Question Analysis: The question tests the understanding of the physical changes occurring in a p-n junction diode under reverse bias conditions.

Step 1 (Governing Principle): [0.5 Mark]
In a p-n junction diode, reverse biasing occurs when the p-side is connected to the negative terminal and the n-side is connected to the positive terminal of an external battery. The external electric field ($E_{ext}$) is directed in the same direction as the internal junction electric field ($E_i$). This results in an increase in the net electric field across the junction.

Step 2 (Step-by-Step Working): [0.25 Mark]

• Barrier Height: Since the external voltage ($V$) opposes the flow of majority charge carriers, the potential barrier ($V_B$) increases by the magnitude of the applied voltage: $V_{new} = V_B + V$.
• Depletion Region: The increased potential barrier requires more energy for charge carriers to cross the junction. To support this higher potential difference, the depletion region must widen to accommodate more uncompensated ions: $W_{reverse} > W_{equilibrium}$.

Step 3 (Final Concluded Answer): [0.25 Mark]
Based on the physical analysis, the barrier height increases and the depletion region widens. Therefore, the correct option is (B).

💡 EL10 Concept Insight: Think of the depletion region like a "no-man's land" at the border; when you reverse bias the diode, you are essentially pushing the soldiers (charge carriers) further away from the border, making the "no-man's land" wider and the "wall" (barrier height) higher to climb.