Indian Institute of Science

You will have to appear for IIT JAM. It is the entrance test for IISc, Bangalore.

Through JEE Mains and Advanced, if you are planning for B.Tech and through GATE if you are planning for M.Tech.

Both are great institutions. But, according to my point of view, IISC have a benefit for researchers.

Yes, OBC cut-off for SB/SX is 45.

All aspirants aiming to build their career in Science related fields must refer to the rankings mentioned at the link provided below in order to make a wise decision while selecting a college. After all, choosing a good college is the foundation stone to build a successful career later. Towards the end, we have also listed the top 50 B.Sc/ M.Sc. Colleges in India in 2016 as mentioned in India Today rankings. https://www.shiksha.com/science/articles/top-10-bsc-msc-colleges-in-india-blogId-13473.