Out of the following statements, which statements explain the difference between forward biasing and reverse biasing in a p-n junction correctly?
| Forward biasing in a p-n junction | Reverse biasing in a p-n junction | |
| (A) | p-side is connected to the +ve terminal and n-side to the -ve terminal of the battery. | p-side is connected to the -ve terminal and n-side to the +ve terminal of the battery. |
| (B) | Depletion layer becomes thicker. | Depletion layer becomes thin. |
| (C) | Resistance across the p-n junction increases. | Resistance across the p-n junction decreases. |
| (D) | the current is due to majority charge carriers. | the current is due to minority charge carriers. |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A) and (D) only
Each row of the table is one statement: it is correct only if both the forward-bias entry and the reverse-bias entry are right.
(A) Forward: p-side is connected to the +ve terminal and n-side to the -ve terminal of the battery. Reverse: p-side is connected to the -ve terminal and n-side to the +ve terminal of the battery. — Correct. This is how the two biasing arrangements are defined.
(B) Forward: Depletion layer becomes thicker. Reverse: Depletion layer becomes thin. — Incorrect. The two entries are interchanged. In forward bias the depletion layer becomes thin, and in reverse bias it becomes thick.
(C) Forward: Resistance across the p-n junction increases. Reverse: Resistance across the p-n junction decreases. — Incorrect. Again interchanged. A thin depletion layer gives a low resistance in forward bias, and a thick one gives a high resistance in reverse bias.
(D) Forward: the current is due to majority charge carriers. Reverse: the current is due to minority charge carriers. — Correct. The forward current is carried by the majority carriers crossing the narrowed barrier, while the tiny reverse current is due to minority carriers.