Question

If the forward bias voltage in a diode is increased, the width of the depletion region

• A. increases
• B. decreases
• C. fluctuates
• D. does not change

Hint:

Forward bias opposes the built-in potential, so more carriers reach the junction.

Answer 1

The Correct Option is B

Step 1: Recall the diode picture:
Think of the depletion layer as a thin zone emptied of carriers. Its width sets how easily current flows. A thin zone means an easy path for current.

Step 2: Use the current idea:
A diode conducts well in forward bias. Large current needs a low barrier and a thin depletion layer. As the forward voltage rises, the current rises sharply, so the layer must be getting thinner.

Step 3: Use the charge idea:
The applied forward field is opposite to the junction field. It pushes majority carriers into the depletion zone, and they cancel the fixed charge there. Less fixed charge means a narrower layer.

Step 4: Rule out the rest:
Widening happens only under reverse bias. Nothing in the diode makes the width fluctuate or stay constant, so the other options do not hold.

Final Answer:
With higher forward bias the depletion width decreases. \[\boxed{\text{decreases}}\]