Concept:Rectification requires unidirectional conduction, which is provided by the asymmetric I-V characteristic of a PN junction.
Formula:$$R_F \approx 1\text{ to } 25\ \Omega \quad \text{and} \quad R_R \approx 10^6\ \Omega \ (\text{M}\Omega)$$
Solution:- Under forward bias, the depletion layer shrinks, providing a low-resistance path (diode conducts).
- Under reverse bias, the depletion layer widens, providing a very high resistance (diode blocks).
- This one-way conduction converts alternating current into unidirectional (direct) current.
Why other options are incorrect:- Option A: Diodes are passive devices that cannot amplify power.
- Option C: Equal bidirectional conduction is the property of a linear resistor, which cannot rectify.
- Option D: The dynamic resistance of a diode is non-linear and highly voltage-dependent.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.