Question

The edge lengths of the cell in terms of the radius of spheres constituting fcc, bcc and simple cubic unit cell are respectively

• A. $2\sqrt{2}r,\frac{4r}{\sqrt{3}},2r$
• B. $\frac{4r}{\sqrt{3}},2\sqrt{2}r,2r$
• C. $2r,2\sqrt{2}r,\frac{4r}{\sqrt{3}}$
• D. $2r,\frac{4r}{\sqrt{3}},2\sqrt{2}r$

Answer 1

Answer: (A)

$2\sqrt{2}r,\frac{4r}{\sqrt{3}},2r$

Answer 2

Edge length of fcc = $2\sqrt{2}r$

Edge length for bcc =$4r/\sqrt{3}$

Ege length of simple cubic = 2r