The gravitational force between a H-atom and another particle of mass m will be given by Newton’s law:
F=G (M.m)/r2 , where r is in km and
(a) M = mproton + melectron.
(b) M = mproton + melectron -B/C2(B = 13.6 eV).
(c) M is not related to the mass of the hydrogen atom.
= magnitude of the potential energy of electron in the H-atom).