B.Sc Physics

You can do any of these as with b.tech you can pursue m.tech and teach in engineering colleges. With bsc physics + msc physics + net you can teach in other colleges too.
if you wish to teach in school, then go for b.ed.

Hi Abhishek,
If possible go through the alumni speak section to get an idea what the alumni thinks about the institute. However, we can help you with the parameters that you can keep in mind while choosing an institute. You can consider the below parameters :
1) Faculty,
2) Affiliation / Recognition
3) Course Material,
4) Quality Education,
5) Fees
6) Infrastructure
7) Success Rate.
8) Placement
9) Top recruiting companies.
I hope this information helps. Please feel free to revert.
Wish you luck.

MEC is normally pursued by those who wish to pursue B Com, CA or any Accountacy track. To pursue B Sc in Sciences, PCM or PCB is normally required.

Bsc in astro physics is a good course for you

colleges in kolkata where you can do is : http://finders.sulekha.com/college-finder/west-bengal/kolkata/b-sc/physics.htm
Colleges in Mumbai are Mithibai colleges, Ruparel college, sathaye college.

Dear abhishek,
Yes you can if you have right skills and knowledge but suggestion from my side you should complete your master degree with B.ed that will give you best tools and understanding towards teaching methodology.
All the best

Definitely if you will complete your graduation, you can coach IIT students too