The contribution of a particle at the edge centre of a particular unit cell is ,

Options

A. `1/2`
B. `1/4`
C. `1`
D. `1/8`

Explanation

To determine the contribution of a particle located at the edge center of a unit cell, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Unit Cell**:
- Consider a cubic unit cell. A unit cell is the smallest repeating unit in a crystal lattice.

2. **Locate the Edge Center**:
- The edge center is located at the midpoint of each edge of the cube. In a cube, there are 12 edges.

3. **Determine Sharing of the Particle**:
- A particle located at the edge center is shared among 4 different unit cells. This is because each edge belongs to 4 adjacent cubes (two cubes above and two cubes below).

4. **Calculate the Contribution**:
- Since the particle is shared among 4 unit cells, the contribution of one particle at the edge center to one unit cell is:
\[ \text{Contribution} = \frac{1}{4} \]

5. **Conclusion**:
- Therefore, the contribution of a particle at the edge center of a unit cell is \( \frac{1}{4} \).

### Final Answer:
The contribution of a particle at the edge center of a particular unit cell is \( \frac{1}{4} \).

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