Hi shiva

thanks for asking your query as for the preparation of jee mains ncerts are considered best because direct questions are asked from it even without changing the values of numericals ,books like MS Chauhan for organic chemistry,Modern physics by hc verma etc are the best books for jee.

there are certain books also which is available online you could use that also.

Dear Aspirant 

There are many books available in the market which you can use to pace your preparations for jee main 2020 but I would like to suggest you some nice book. 

• Physical chemistry by narendra Avasthi. 
• Organic chemistry by Ms Chauhan. 
• Inorganic chemistry by Vk Agrawal. 
• Maths arihant publication. 
• Maths for jee main and advanced by cengage publications. 
• Physics arihant publication. 
• Physics by HC VERMA. 

Good luck for your future :) 

Feel free to ask if you have any further queries.