According to Bohr's atomic theory :-
(1) Kinetic energy of electron is $\propto \frac{\mathrm{Z}^2}{\mathrm{n}^2}$.
(2) The product of velocity (v) of electron and principal quantum number ( n ), ${ }^{\prime} \mathrm{v}_{\mathrm{n}}{ }^{\prime} \propto \mathrm{Z}^2$.
(3) Frequency of revolution of electron in an orbit is $\propto \frac{\mathrm{Z}^3}{\mathrm{n}^3}$.
(4) Coulombic force of attraction on the electron is $\propto \frac{\mathrm{Z}^3}{\mathrm{n}^4}$.
Choose the most appropriate answer from the options given below :