APC Books is an essential reading for all students. They have a diverse selection of books for numerous fields. Sample papers and MCQ books are also accessible. You will certainly succeed if you study from APC Books.

Use HC verma for physics and give special attention to derivations 40% physics paper contain derivations

It's really easy to score 90% in boards if u r from CBSE because I can tell u only about that.
Just focus on ncert that's enough board exam has a very standard pattern and the same topics from which questions are asked .
Just complete ur ncert that's more than enough...

Hi Gayatri ! For 12th board , you should focus only on your syllabus books like if you are studying in CBSE than CBSE books & If other state board than Go through NCERT books only. Avoid Any other reference or guides. Good luck !! Rajat Dave ( CR @ Career 360 )

Syllables book is best for studies