3.2kg of iron is required to make a hollow spherical shell having inner radius (r=3cm).outer radius(r=5cm). i)estimate density of iron. (ans :6.585g/cm^3) -not sure if its correct though ii) using (i),est interatomic spacing of the iron atoms. the atomic mass of iron is 55.9u. need help in (ii).is there like a formula for it?