Limitations of Rutherford's model :-

although Rutherford's model was accepted all over the world but It was having a big mistake which remain unnoticed , Rutherford said that the electron revolves around a nucleus in a spiral path it means that , Electron will fall into the nucleus at a time , But it was nothing like that , If electron will fall into the nucleus then there will be no electrons present in that & it will become unstable & it will got destroyed at a time , But it was nothing like that .

Bohr's Theory :- This mistake got modified by bohr & he proposed his model & saying that electron will not follow a spiral path it will follow a circular path , so that the atom is stable , but although after this His theory also has some limitations those are :-

1. Bohr's model of an atom is valid only for hydrogen & hydrogen alike atoms , For He or any other atom it got failed.

2. Although bohr's said that electron will revolve around a nucleus in a circular path but he was not able to explain that why he has choosen circular paths ? Electrons also can revolve around nucleus in an elliptical path .
R model cannot explain stability of atom while b model cannot explain spectrum