The number of points at the centre of the primitive unit cell is

Options

A. 1
B. 0
C. 2
D. 3

Answer

To solve the question regarding the number of points at the center of a primitive unit cell, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Primitive Unit Cell**:
- A primitive unit cell is the smallest repeating unit in a crystal lattice that can be used to construct the entire lattice by translation. It contains only one lattice point.

2. **Visualizing the Unit Cell**:
- Imagine a cubic unit cell. In a primitive cubic unit cell, there are atoms located at the corners of the cube.

3. **Identifying the Center of the Unit Cell**:
- The center of the cubic unit cell is the point located exactly in the middle of the cube.

4. **Counting Points at the Center**:
- In a primitive unit cell, there are no atoms or lattice points located at the center. The only lattice points are at the corners of the cube.

5. **Conclusion**:
- Therefore, the number of points at the center of the primitive unit cell is **zero**.

### Final Answer:
The number of points at the center of the primitive unit cell is **0**.

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