Concept:Reverse biasing occurs when an external voltage increases the potential difference across the depletion layer by making the N-region positive with respect to the P-region.
Formula:$$V_{\text{net}} = V_0 + V_R \quad \text{where } V_{\text{anode}} < V_{\text{cathode}}$$
Solution:- Connecting the negative terminal to the P-region pulls holes away from the junction.
- Connecting the positive terminal to the N-region pulls free electrons away from the junction.
- This widens the depletion layer, increasing the junction resistance and preventing majority carrier conduction.
Why other options are incorrect:- Option A: Making the P-region more positive than the N-region forward-biases the diode.
- Option B: The positive half-cycle of an AC signal forward-biases a normally oriented diode.
- Option D: Large forward diffusion current is the defining characteristic of forward bias.
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