AIM, you can't simply become a physics lecturer just by qualifying JEE Mains. I will describe the steps you need to follow after that to achieve your goal.

To become a professor of Physics, a research degree is must and especially a phD degree in Physics.

You should have passed 10th standard with a minimum first class.

You should have also passed 12th standard with minimum first class .

Next you need to complete a three year bachelor degree and obtained pass. As you desire of becoming a professor of physics, you are expected to have passed BSc Physics with a minimum first class. Studying Physics related degree is only mandatory and not any other subjects. Completing BSc students can either apply for direct PhD or take a masters route.  So you should study a MSc Physics and obtain first class in this case.

Next, write GATE exam and obtain high rank if your focus is studying at IIT institutions. If you dont want to study at IIT, and want to consider other institutions then a UGC-NET score/ CSIR score is essential. You are also expected to have passed UGC-JRF to be eligible for monthly stipend during PhD.

So completing a Phd, you can work at colleges and universities directly as an Assistant professor and after few years of experience and good performance you are likely to be promoted as a Professor.

For studying a PhD in Physics, you can consider top institutes from India like

• IIT institutions
• IISC Bangalore
• BITS Pilani
• University of Delhi
• University of Mumbai
• University of Calcutta
• VIT University
• Anna university

Feel free to ask if you have any more queries.

Hope this helps!

All the best!