Dear Raj, IIT JAM is the entrance examination for pursuing M.Sc courses in IITs. For being eligible for M.Sc in Physics, you should have studied Physics for atleast 2 years or 4 semesters and Mathematics for atleast 1 year or 2 semesters. If you do fulfil this criteria, then you should have secured a minimum aggregate of 55% in your Bachelor's degree if you belong to General/OBC Category and 50% if you belong to Reserved Categories. For more information, please visit our page at; https://university.careers360.com/articles/jam-eligibility-criteria