Suggest some chapters in physics to score 80 in mains

In JEE main questions are asked from each chapter unlike JEE advance but there are possibly few chschapt which you can give more importance this are

Rotational motion

Electrostatics

Modern Physics

Optics

You should take help of previous years question to understand the importance of every chapters.

Every chapter has it's own importance.

For example if a student doesn't know what is current, potential difference, etc. then he/she will not understand what is Kirchhoff's Law.

Similarly a student won't understand what is differentiation if he/she doesn't know what is continuity and vice versa.

Every chapter is thus important.

If you still have any queries feel free to ask in the comment section down below.