In a PN junction

Options

A. high potential at N side and low potential at P side
B. high potential at P side and low potential at N side
C. P and N both are at same potential
D. undetermined

Answer

To solve the question regarding the potential in a PN junction, we will analyze the characteristics of a PN junction diode step by step.

### Step-by-Step Solution:

1. **Understanding the PN Junction**:
- A PN junction is formed when p-type and n-type semiconductors are joined together. The p-type semiconductor has an abundance of holes (positive charge carriers), while the n-type semiconductor has an abundance of electrons (negative charge carriers).

2. **Formation of the Junction**:
- When the p-type and n-type materials are brought into contact, electrons from the n-type region will diffuse into the p-type region where there are holes. This process leads to recombination, where electrons fill the holes, creating a depletion region at the junction.

3. **Charge Carrier Movement**:
- As electrons move from the n-side to the p-side, they leave behind positively charged ions in the n-region. Conversely, the p-side will have negatively charged ions due to the absence of holes. This creates an electric field across the junction.

4. **Establishing Potential**:
- The electric field generated by the ion charges creates a potential difference across the junction. The side with the positive ions (n-side) will have a higher potential, while the side with the negative ions (p-side) will have a lower potential.

5. **Conclusion**:
- Therefore, in a PN junction, the high potential is at the n-side and the low potential is at the p-side. This leads us to conclude that the correct answer to the question is:
- **High potential is at the n-side and low potential is at the p-side.**

### Final Answer:
- The correct option is: **High potential is at n side and low potential is at p side.**