Question

When forward bias is applied to a p-n junction, then the potential barrier and the width of the depletion region respectively.

• A. increases, increases.
• B. decreases, increases.
• C. increases, decreases.
• D. decreases, decreases.

Hint:

Forward bias opposes the built-in field of the junction, so the barrier shrinks and the depletion layer narrows.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
In a p-n junction a depletion region and a potential barrier exist at the junction.

Step 2: Effect of forward bias
In forward bias the p side is connected to the positive terminal. The applied field opposes the barrier field, so the potential barrier decreases.

Step 3: Depletion width
A lower barrier lets majority carriers move towards the junction and fill the depletion region, so its width decreases.

Step 4: Compare the options
Both the barrier and the width decrease, which matches the last option.

Final Answer:
In forward bias both the potential barrier and the depletion width decrease. \[ \boxed{\text{(D) }\text{decreases, decreases.}} \]