Dear Rajkumar,

IISER and IISC are reputed institutions that offers a bachelor in science degree. JEE Advance is a exam through which you can get a chance to be admitted in these two institutions. IISER eligibility criteria is to secure a rank within top 10000. And IISC Bangalore requires you to secure a rank within 250 if you are general, 6000 if you are OBC,  8000 if you are SC and 50000 if you are of ST category. Hope this clears your doubt.