Hello Shamik,
You can get admission in IISC for IG Courses through the following exams:-
1) KVPY
2) JEE MAINS
3) JEE ADVANCED
4) AIPMT
In JEE MAINS AND ADV. a candidate needs w minimum of 60% ( for general category ) score in it to get admission in IISC.

Hi Shamik, the admission process takes place with the scores of the candidate in the national exams mentioned below. The national exams are, 

1) KVPY 

2) IIT JEE Mains 

3) IIT JEE Advanced

4) NEET UG

You need to have very high scores in these exams to get through to the top college of India. You also need to have a minimum 60%+ in your 10th and 12th scores as well. Though they mention it minimum 60 percentage, they expect more than 80+ usually. You can refer to the below link, to get more knowledge on the process and other details, 

https://www.iisc.ac.in/ug/info_brochure.html

IISc Bangalore

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