Which of the following lattices has the highest packing efficency (a) simple cubic, (b) body-centred cubic, and (c ) hexagonal close-packed lattice?

Explanation

To determine which of the given lattices has the highest packing efficiency, we will calculate the packing efficiency for each type of lattice: simple cubic, body-centered cubic (BCC), and hexagonal close-packed (HCP).

### Step 1: Understand Packing Efficiency
Packing efficiency is defined as the fraction of the volume of the unit cell that is occupied by the atoms. It can be calculated using the formula:

\[ \text{Packing Efficiency} = \frac{\text{Volume of atoms in the unit cell}}{\text{Volume of the unit cell}} \times 100\% \]
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