Just NCERT books are not enough to get good marks in JEE main for different subjects conditions for different you consider chemistry then most of the questions will come from directly from NCERT but not the case with other subjects in case of Physics you can go through NCERT but for most of the students find it difficult to understand the concept kapali from NCERT and therefore they take help from other books so if you are able to understand concept properly from the NCERT physics then it's good and I am sure that no other concepts will be house in the exam part from NCERT specific to Physics so it depends upon your level of understanding and the Teachers India's of mathematics I would say half of person you can solve from NCERT basic knowledge but again in mathematics if you practice a lot of problems then it will be better slow NCERT is must but for more practice you need to refer other books for variety of questions.