Question

What is the radius of the nucleus of 28/14 Si ? What is its volume?

Answer 1

$$R={(1.3\:\rm fm)}\:A^{1/3}\\ =(1.3\:\rm fm)\:28^{1/3}=3.95\:\rm fm$$

$$V=\frac{4}{3}\pi R^3\\ =\frac{4}{3}*3.14*(\rm 3.95\: fm)^3=258\: fm^3$$