Question

If 'a' stands for the edge length of the cubic systems : simple cubic, body centred cubic and face centred cubic, then the ratio of radii of the spheres in these system will be respectively –

• A. $\frac{1}{2}$a :$\frac{\sqrt{3}}{2}$ a : $\frac{\sqrt{2}}{2}$ a
• B. 1a : $\sqrt{3}$a : $\sqrt{2}$a
• C. $\frac{1}{2}$a :$\frac{\sqrt{3}}{4}$ a : $\frac{1}{2\sqrt{2}}$a
• D. $\frac{1}{2}$a : $\sqrt{3}$a : $\frac{1}{\sqrt{2}}$a

Answer 1

Answer: (C)

$\frac{1}{2}$a :$\frac{\sqrt{3}}{4}$ a : $\frac{1}{2\sqrt{2}}$a

Answer 2

sc 2r = a

fcc 4r = $\sqrt{2}$a

bcc 4r = $\sqrt{3}$a