Very little current flows through a reverse biased diode because:
Athe applied voltage is far too small to matter
Bthe diode's resistance drops close to zero
Cthe depletion layer widens and blocks majority carriers
Dthe semiconductor melts at that polarity
Answer & Solution
Correct answer: C. the depletion layer widens and blocks majority carriers
1. Reverse bias connects the positive supply terminal to the n-side and the negative to the p-side.
2. That pulls the majority carriers away from the junction rather than across it.
3. The depletion layer therefore widens, raising the barrier the carriers must cross.
4. Majority carriers are blocked, so only a very small leakage current from minority carriers flows.
5. Resistance in reverse bias is very high, not near zero, which is precisely why the diode conducts in only one direction.
_Source: NECTA ACSEE 2023 Physics 131/1, Question 9: Electronics (Semiconductors,Logic Gates & Op-Amps)_