Hello Dharmendra Kumar Pandit. Thanks for contacting Careers360 and we hope we will be able to answer your query.
Please note that the IISERs are among the premier academic institutions in the country that accept admissions to its courses through JEE Advanced ranks. So, obviously the level of input you should put into your JEE preparation should be quite high.
I would like to direct your attention to this link for more information about the cutoffs for IISERs:
Also, please see the eligibility criteria here:
Hope this helps you and all the best!
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