Q.
In a hydrogen-like species, the net force acting on a revolving electron in an orbit as given by the Bohr model is proportional to [ n→ principal quantum number, Z→ atomic number]
The net force on a revolving electron is F=rmv2 F∝rnvn2
The velocity of the electron in the nth shell vn∝nZ
and the radius of the nth shell rn∝Zn2 ⇒F∝n4Z3