Why did the work of Rutherford and Marsden convince many scientists that the 'plum pudding' model of the atom was incorrect?

Because the alpha particles were passing through the foil with slight to no reflection however some alpha particles were deflected with high angle or reversed direction which is not what was expected as according to thomson the atom is a lump of postively charged mass and there will be no deflection as the charge is distrbuted and the charge of alpha particle is 207 times that of electron