Forward bias applied to a p-n junction diode

The correct answer is Option (3) → decreases the electric field in the depletion region

In a p-n junction diode:

• The depletion region is formed due to diffusion of carriers, leaving behind immobile ions that create an electric field opposing further diffusion.

• When forward bias is applied, the external voltage reduces the potential barrier across the junction.

• This reduction in barrier potential decreases the width of the depletion region.

• Consequently, the electric field inside the depletion layer also decreases, allowing majority carriers to flow across the junction.

Therefore, the correct effect of forward bias is: it decreases the electric field in the depletion region.