Question

If p-n junction diode is forward biased then

• A. width of depletion layer decreases.
• B. width of depletion layer increases.
• C. barrier voltage increases
• D. electric conduction is not possible

Hint:

Forward bias reduces the barrier and the depletion layer.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
In forward bias, the p side is connected to the positive terminal and the n side to the negative terminal. The applied voltage opposes the built-in barrier potential.

Step 2: Effect:
The majority carriers are pushed towards the junction. The depletion region becomes narrower and the barrier voltage drops. Current can flow easily.

Step 3: Check the options:
(A) depletion layer width decreases, which is correct. (B) increases happens in reverse bias. (C) barrier voltage decreases, not increases. (D) conduction is possible above the knee voltage. So (A) is correct.

Final Answer:
Forward bias narrows the depletion layer. \[ \boxed{A} \]