Question

If I have a positive charge at the origin, and a neutral atom of polarizability alpha replaces a permament dipole at (x,0,0), what is the direction of the induced dipole moment in the polarized atom? comment on the relation of the magnitude of the induced dipole moment and the separation x? Why do we assume s is bigger than L and x?

Answer 1

So as positive charge is placed at origin then it will induce negative charge on neutral atom placed at (x,0,0) so as we know dipole moment is directed from negative to positive so direction of dipole moment is along -x direction

so as dipole moment is proportional to Electric field produced at point x due to dipole moment on axis

so,

or

where alpha is polarizability which is constant

as electric field varies as inverse cube of distance

so dipole moemnt also

and please spacify what is s elaborate more.