Question

Which of the following does not represent radius of the atom correctly?

• A. Simple cubic cell : Radius$=\frac{a}{2}$
• B. Face centered cubic cell : Radius$=\frac{a}{3\sqrt{3}}$
• C. Body centered cubic cell : Radius$=\frac{\sqrt{3}}{4}a$
• D. All

Answer 1

Answer: (B)

Face centered cubic cell : Radius$=\frac{a}{3\sqrt{3}}$

For $FCC$ crystals,

$a=2\sqrt{2}rr=\frac{a}{2\sqrt{2}}$.

So, option B is not correct.