Hello Abhishek,

To be eligible for colleges that comes under JEE MAINS exam you need to score at least 75% or above to be eligible for any colleges under JEE MAINS.

It is mandatory for candidates to have taken 5 subjects in class XII or equivalent qualifying exam

The 5 subjects for B.Tech/ B.E. are:

1-Language, 2-Physics, 3-Mathematics, 4-Any one of (Chemistry, Biology, Biotechnology, Technical Vocational Subject), 5-Any other subjects

Hope it helps you 

Thank you