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]

Step-by-step solution

The net force on a revolving electron is F = m v 2 r F ∝ v n 2 r n The velocity of the electron in the n th shell v n ∝ Z n and the radius of the n th shell r n ∝ n 2 Z ⇒ F ∝ Z 3 n 4