is the study material provided by the coaching institutes sufficient for the preparation of iit-jee?

Answer 1

No certainly not , because it is jungle out there in the open competitive field every single mark makes world of difference to each one of you competing the exam.So try and get hold of as many question papers as possible solve them this way you will come to know the pattern in which they are testing you and you will not be surprised in your main exam also you get good exposure to the variety of question.