Question

The space occupied by spheres in bcc arrangement is

• A. $74$%
• B. $70$%
• C. $68$%
• D. $60.4$%

Answer 1

Answer: (C)

$68$%

The space occupied by spheres in bcc arrangement is 68%.
The empty space is 32%.

Packing fraction $=\frac{Z\times \frac{4}{3}\pi r^3}{a^3}=\frac{2\times \frac{4}{3}\pi r^3}{(\frac{4r}{\sqrt{2}}{)}^3}=0.68=68$%