The approximate size of the nucleus of Ni (mass number-64) is_____
a) 3 fm
b) 4 fm
c) 5 fm
d) 2 fm

Nuclear sizes obey roughly the following empirical relation


: r=R₀ A ^1/3


where r is the radius of the nucleus
R₀ is a constant whose value is equal to 1.25 fm  (femo meters units)
A is atomic mass of element