can you please help me out with the best book i should refer ( physics, chemistry maths) i am in class 11 cbse.

also i would like to know from where can i get the previous year question paper for practise.?

u can use r.d. sharma and m.l.khana for maths ,,h.c. verma and pradeep for physics ,,, pradeep for chemistry . ncert books of P.C.M. 

The best books are

M L Khanna ,Arihant Series and TMH for Maths

I E Irodov ,resnick Halliday Walker and H C Verma for Physics.

Organic-tondon and morrison and boyd

Inorganic-J D lee and tondon

Physical-P bahadur,O P Aggarwal and P w Atkins

past papers there is a book of arihant which you can get online.

ALL THE BEST!!