Question

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

• A. $\frac{1}{2}$
• B. $\frac{1}{4}$
• C. 1
• D. $\frac{1}{8}$

Answer 1

Answer: (B)

An atom at the edge centre is shared by four unit cells in the lattice and hence, contributes only $\frac{1}{4}$ th to a particular unit cell

Also, there are 12 edge centres in a unit cell. Thus, total number of atoms at the edge centres per unit cell.

$-12\times \frac{1}{4}-3$