(a) Draw the graph showing the variation of the number (N) of scattered alpha particles with scattering angle ($\theta$) in Geiger - Marsden experiment. Infer two conclusions from the graph. OR (b) Plot suitable graphs to show the variation of photoelectric current with the collector plate potential for the incident radiation of (i) the same intensity but different frequencies $\nu_1, \nu_2$ and $\nu_3$ ($\nu_1 < \nu_2 < \nu_3$) (ii) the same frequency but different intensities $I_1, I_2$ and $I_3$ ($I_1 < I_2 < I_3$)