please can anyone tell me what are the physics chapter of class 11 that are very useful for class 12 ( jee main) ?

Hi,

So weightage wise

1. Rotational dynamics(Moment of inertia most imp.[1que.] , Total 1–2 ques.)
2. SHM(moderately difficult 1 ques. )
3. Thermal physics (Easy and scoring 2–3ques.)
4. Kinematics(1 ques. Easy )
5. Work, power and energy (2–3ques.)
6. COM and collisions(1–2ques.)

By the way one TIP I would share is try practicing multi-concept ques. (like kinematics + electrostatics) more because JEE Mains is shifting towards testing you in multi chapters, you can verify this by looking JEE Mains papers of 2019 and 2020, 2021.

As well as refer to this list also :-

1. unit and dimensions - you just have to cover the theory and go through past year questions
2. Gravitation - there are two parts of this chapter ,one resembles with electrostatics and the other one is satellites and kepler laws .At least cover the second part
3. Heat transfer - the concepts in this chapter are very limited and some times direct formula based questions are asked .
4. Calorimetry- this chapter also have very limited concepts and can give you +4 in exam if you practise some questions
5. waves and sound - The important topics in this chapter are doppler effect and some other direct formula based questions
6. Fluid - go through basic concepts like continuity equation ,bernoullie equation. Some times you can encounter direct question on easy topics like continuity equation so cover the basics of this chapter.

Hope this helps.

All the best.