Explain how much portin of an atom located at (a) corner and (b) body centre of a cubic unit cell is part of its neighouring unit cell.

Explanation

To solve the question regarding the portion of an atom located at the corner and body center of a cubic unit cell that is part of its neighboring unit cell, we can break it down into two parts:

### Step 1: Contribution of an Atom at the Corner of a Cubic Unit Cell
1. **Understanding the Position**: In a cubic unit cell, there are atoms located at each of the eight corners.
2. **Shared Atoms**: Each corner atom is shared among eight neighboring unit cells (the unit cell itself and the seven adjacent unit cells).
3. **Calculating Contribution**: Since one atom at the corner is shared by eight unit cells, the contribution of one corner atom to a single unit cell is:
\[
\text{Contribution} = \frac{1}{8}
...