Books play an important role in the preparation of any exam. So always prefer the best reference books to prepare. For board exams I suggest you NCERT Books, they cover the whole syllabus and designed in a proper manner. They can also helpful in the preparation of JEE Main. Here are some reference books for JEE Main which are cruicial in your preparation.

Physics

Concepts of Physics Volume I and II - H. C. Verma

Fundamentals of Physics - Halliday, Resnick & Walker

Problems in General Physics - I. E. Irodov

A Collection of Questions & Problems in Physics - L.
A. Sena

Physics Volume 1 & 2 - Tipler

Chemistry

Organic Chemistry - Morrison Boyd, O. P. Tandon

Inorganic Chemistry - O. P. Tandon

Modern Approach to chemical calculation - R. C. Mukherjee

Numerical Chemistry - P. Bahadur

Concise Inorganic Chemistry - J. D. Lee

Maths

Mathematics for Class 11 & Class 12 - R. D. Sharma

Maths for Class 11 & Class 12 - R. S. Agarwal

IIT Mathematics - M. L. Khanna

Problems in Calculus of One Variable - I. A. Maron

Yes, NCERT books are best. You will find questions similar to it. But you can use reference books also i.e. along with ncert books.

Best of luck!

Hi Ronak

Yes the basic questions in the IIT JEE are always from the NCERT. Even you can find the ditto lines in the exam from the NCERT.

For Physics you can use HC Verma, Chemistry by Pradeep and Maths from RS Aggarwal/RD Sharma.

Hope this helps you. :)