In a p-n junction,a potential barrier of 250 mev exsists across the junction.A hole with a kimetic energy of 300 meV approaches the junction. Find the kinetic energy of the hole when it crosses the junction if the hole approached the junction (a)from the p-side and (b)from the n-side.

Explanation

To solve the problem, we need to analyze the situation of a p-n junction and how the potential barrier affects the kinetic energy of a hole approaching the junction from both the p-side and the n-side.

### Step-by-Step Solution:

1. **Understanding the Potential Barrier**:
- A potential barrier of 250 meV exists across the p-n junction. This means that any charge carrier (like a hole) needs to overcome this barrier to cross from one side to the other.

2. **Kinetic Energy of the Hole**:
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