Hiiiii Neha !!!!!!

Best book for JNU Entrance exam are -

1. Physics by Resnick and Halliday 

2. JNU ENTRANCE M. SC. Physics by Vishal Deoarshi and Jyoti Ahuja.

3. M.Sc. Entrance Entrance Examination by Dr. N. K. Nayyar and Dr. Vishal Mishra...

4.  Msc Entrance Examination by Khanna Publisher...

I suggest you to solve the question paper of previous year. Clear your concepts, manage your time,  give yourself enough time to study, use flow chart and diagram, take regular breaks, organise group study, taking healthy foods, drink plenty of water.... Hope this information help you... Thank you