Can I get admission in Physics grad school having done my undergrad in mechanical engineering?

I am a mechanical engineering undergrad in a prestigious Indian university having good academic scores. I have self taught myself undergrad level physics and mathematics. I am planning to give the general and the physics GRE. I also have a research paper published in the mechanical engineering sector. Assuming I get good scores in my GRE's, what chances would I have on getting an admit if I apply to top physics grad schools in USA or other countries?