For getting admission in BSc Research Physics you have to ways:

1. KVPY
2. JEE ADVANCED

Via KVPY with good marks after qualifying the interview you will get a fellowship along with a chance to get admission in IISC.

For the second way out you have to qualify in JEE MAINS exam and then you have to qualify JEE ADVANCED and by getting a good rank you can opt for BSc Research Physics.

I hope my answer helps you. All the very best for your future endeavors!