question_answer

                        If 'a' stands for the edge length of the cubic systems simple cubic, body-centre cubic, and face-centered 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) \[la:\sqrt{3a}:\sqrt{2}a\]

C) \[\frac{1}{2}a:\frac{\sqrt{3}}{4}a:\frac{1}{2\sqrt{2}}a\]

D)   \[\frac{1}{2}a:\sqrt{3}a:\frac{1}{\sqrt{2}}a\]