1  INTRODUCTION
In the previous chapter, we have learnt that in every atom, the positive
charge and mass are densely concentrated at the centre of the atom
forming its nucleus The overall dimensions of a nucleus are much smaller
than those of an atom Experiments on scattering of a-particles
demonstrated that the radius of a nucleus was smaller than the radius
of an atom by a factor of about 104 This means the volume of a nucleus
is about 10–12 times the volume of the atom