(a) Explain with the help of suitable diagram , the two processes which occur during the formations of a p -n junction diode . Hence , define the terms :
(i) depletion region and (ii) potential barrier :
(b) Draw a circuit diagram of a p - n junction diode under forward bias and explain its working .

Explanation

### Step-by-Step Solution

#### (a) Formation of a p-n Junction Diode

1. **Understanding the p-n Junction**:
- A p-n junction diode is formed by joining p-type and n-type semiconductors. 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. **Diffusion Process**:
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