A cubic unit cell has eight edge-centres. (true/false)

Explanation

To determine whether the statement "A cubic unit cell has eight edge-centres" is true or false, we will analyze the structure of a cubic unit cell step by step.

### Step-by-Step Solution:

1. **Understanding the Structure of a Cubic Unit Cell:**
- A cubic unit cell is a three-dimensional structure with equal edge lengths and right angles between edges. It has 8 corner atoms and 12 edges.

2. **Identifying Edge Centres:**
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