Hey Mani.

The marks required for admission in any government medical college would totally depend on various different factors like the level of difficulty, competition, no of student, state you belong to etc. You'd require a score of atleast more than 510 marks for admission under the State quota. And for admission under the All India quota you'd required a score above 560 marks atleast. But the state that you belong to would also vary the lowest marks required a lot. 

Best of luck