Hello dear aspirant,
There are a lot of government universities which will give you admission on 78.8%, but your chances of getting admission in top universities like the university of Delhi and university of Mumbai is very less. For Delhi university, the cutoff for B. Sc Physics Or maths is usually high, closing cutoff at 88% , same is the case with the University of Mumbai. Still, there are numerous other universities which can give you admission, like the Punjab university and the CCSU and Jaipur university,  some good colleges of Bangalore and chennai.
Please do mention the university that you want to take admission in, so that I can answer more relavently.
Hope it works.

Hello student as you didn't mention the region/state its bit difficult to answer still I'm trying to mention some of the best bsc colleges of India. But I request you to plz help me with the state/ region so that I can provide you exact information.

Best bsc colleges in India are mentioned below
1)University of delhi
2)loyola college chennai
3)christ University bengaluru
4)fegrusson college pune
5)madras Christian college chennai
6)St xaviers college mumbai
7) University of Calcutta
8)jatin University bengaluru
9)Mumbai University
10)Banaras hindu University

Feel free to comment if you have any doubt
Good luck