Question

In a P-N junction diode, which is not connected to any circuit,

• A. Potential is the same every where
• B. The P-type side is at a higher potential than the N-type side
• C. There is an electric field at the P-N junction, directed from the N-type side towards the P-type side
• D. There is an electric field at the junction directed from the P-type side towards the N-type side

Answer 1

The correct option is C There is an electric field at the P-N junction, directed from the N-type side towards the P-type side

At the P-N junction, the electrons from P-type region move into the N-type region creating a thin layer, called depletion layer. The part of depletion layer within the P-region contains negative ions, while the part in N-region contains positive ions.

As a result of this, an electric field $\left(E_i\right)$ is set up in the depletion layer (as shown below. $E_i$ is directed from N-region towards P-region.

Hence, $\left(C\right)$ is the correct answer.