Physics

Your rank would be between 20-30k.

Yes, after 12th it is not necessary to go in your subject field. Presently, it is mandatory to do that so that you can do whatever you want.

Dear Rajat,
You cannot get admission in any college unless you clear your subjects with the qualifying marks.

Top Law Colleges where you can pursue a 3-year LL.B. Course in India are mentioned at the link provided below. This ranking is based on college rankings published by India Today and The Week. https://www.shiksha.com/law/ranking/top-law-colleges-in-india/56-2-0-0-0.

In PAT, there will be asked you 50 questions from physics, 50 questions from chemistry and 100 questions from mathematics or agriculture whichever subject you have.

Hello dear,
You can work as Observations scientist, Assistant Scientist, Quality control Manager, Laboratory technician, School Science Technician or Research Analyst in any government or private institutions. Private Sector Jobs after M.Sc. Physics: There are many opportunities available in IT Field for Physics graduates. Thanks for connecting with Shiksha.com.

Listen student,
All subjects have their own way of career options. It's your hobby and expertise to choose the right subject in graduation. At first, decide about your career options.