Hello dear student, 

Greetings! 

Marks obtained in B.Sc has just the role of fulfilling the eligibility of IIT JAM but it has no role in deciding your rank and results,  these things depend completely on your performance in the entrance. To be eligible for IIT JAM  Candidates should have a bachelor's degree in any stream from any recognized college or university. Percentage Criteria: Students must have obtained minimum 55% marks for general & OBC-NCL candidates and 50% marksfor SC, ST and PwD categories.

thankyou