A2A
Well , I Would say they are more than enough for getting 90+ or even getting 95+ in class 12th boards provided you have done JEE preparation religiously .
If I specifically talk about CBSE board then getting marks in CBSE Boards is a child’s play for a serious JEE aspirant . I Literally picked up the books 3 days before the exam and ended up scoring 96% . More amusingly I purchased physical education book 2 days before my board exam (i guess around 10th april) and still got 96 in boards in it.
Scoring in physics , chemistry and maths is really easy for a jee aspirant . you just need to read the NCERT textbook and solve the problems given in the exercises. That will be more than enough for scoring in PCM in boards