Question

In an atomic bcc lattic what fraction of edge is not covered by atoms?

• A. 32
• B. 0.16
• C. 0.134
• D. 0.268

Answer 1

The correct option is C 0.134

Edge not covered by atom $=a-2r$
also in bcc, $4r=\sqrt{3}a$
Therefore, edge not covered
$=a-\frac{\sqrt{3}}{2}a=a\left(\frac{2-\sqrt{3}}{2}\right)$
$\Rightarrow$ Fraction of edge not covered by atoms
$=\frac{2-\sqrt{3}}{2}=0.134$