In the spectrum of hydrogen atom, the ratio of the longest wavelength in Lyman series to the longest wavelength in the Balmer series is

$\sqrt{d_{1}}$ and $\sqrt{d_{2}}$ are the impact parameters corresponding to scattering angles $60^{\circ}$ and $90^{\circ}$ respectively, when an $\alpha$ particle is approaching a gold nucleus. For $d_{1}=x d_{2}$, the value of $x$ will be ________

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

According to the Rutherford’s atomic model, the electrons inside the atom are

According to classical theory, the circular path of an electron in Rutherford atom is