Question

Packing efficiency of $fcc$ lattice is

• A. $\frac{\pi}{3 \sqrt{2}}$
• B. $\frac{\pi}{2 \sqrt{3}}$
• C. $\frac{\sqrt{3} \pi}{8}$
• D. $\frac{\pi}{6}$

Answer 1

Answer: (A)

For $FCC$ lattice Packing efficiency
$=\frac{4 \times \frac{4}{3} \pi r^{3}}{a^{3}}=\frac{\frac{16}{3} \pi r^{3}}{16 \sqrt{2} r^{3}}$
$=\frac{\pi}{3 \sqrt{2}} .$