The graph which depicts the results of Rutherform gold foil experiment with $\alpha$ -particales is

$\theta:$ Scattering angle

$\mathrm{Y}:$ Number of scattered $\alpha$ -particles detected

(Plots are schematic and not to scale)

The ratio between total acceleration of the electron in singly ionized helium atom and hydrogen atom (both in ground state) is

Ratio of longest wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is

The energy of hydrogen atom in $n^{th}$ orbit is $E_n$, then the energy in $n^{th}$ orbit of singly ionised helium atom will be

Explain Rutherford's explanation for scattered $\alpha $ -particles.