The gravitational force between \(H\text-\)atom and another particle of mass \(m\) will be given by Newton's law \(F=\dfrac{GMm}{r^2},\) where \(r\) is in km and
1. \(M = m_{\text{proton}}+ m_{\text{electron}}.\)
2. \(M = m_{\text{proton}}+ m_{\text{electron}}-\frac{B}{c^2}\left(B= 13.6~\text{eV}\right)\).
3. \(M\) is not related to the mass of the hydrogen atom.
4. \(M = m_{\text{proton}}+ m_{\text{electron}}-\frac{|V|}{c^2}(|V|=\) magnitude of the potential energy of electron in the \(H\text-\)atom).
(2) Hint: There is reduction in the mass as some mass is lost in the form of energy.
Step 1: Find the value of M.
Given,
F=GMmr2
M=effective mass of hydrogen atom
=mass of electron+mass of proton-B2C
where B is BE of hydrogen atom=13.6 eV