The nuclear radius is of the order of 10−13  cm while atomic radius is of the order 10−8  cm. Assuming the nucleus and the atom to be spherical, the fraction of the atomic volume occupied by the nucleus is

The volume of a sphere 4π  r3/3, where r is the radius of the sphere.∴   Volume  of  the  nucleus  = 4π  r3/34π10−133/3  cm3Similarly,  volume of  the  atom=4πr3/3 = 4π10−83/3  cm3Fraction  of  the  volume  of  atom occupied  by the  nucleus=4π10−133/3  cm3 4π10−83/3  cm3=10−15