Physics

Dear Lakshay, there are many courses that you can opt for after class 12th. B.Tech is all time favorite, but then life doesn't stop here only. You have various other good options available.
If you are interested in pursuing a course in science, you can go for various B.Sc like Physics, Chemistry, Maths etc. Other than these, you have specialized ones like Biotechnology, Biochemistry, Microbiology, Forensic, Agriculture, Food technology, Computer Science, etc. Apart from these you have honors courses too. You can also go for paramedical courses like Pharmacy, Ayurveda, etc.
Other than science stream, you can have a career in Journalism, Film and TV production, Management, Hotel Management, Fine Arts, Performing Arts, Physical Education, Yoga, etc too.
There are many reputed universities like Lovely Professional University, VIT University, SRM University, etc that are offering a wide variety of courses to choose from. Some of the universities offer good scholarships too.
Check some of these universities for more details.
Good luck.

It is possible to do MS abroad after a 3-year Bachelors degree. The basic criteria for checking your eligibility for getting admitted in a course is that whether you completed the prerequisite subjects for the graduating course you
have applied for. If yes, then you are welcome but if not, then your UG is considered as non-eligible or you may have to do 23 extra subjects in your Masters, in order to complete your credits. You need to get all of your transcripts (the university degree and marksheets attested by the university) evaluated by WES (World Education Services) (if you are planning on doing MS in USA. They will evaluate all your documents and tell you if your degree is equivalent to USA Bachelor's degree or not
Coming to the countries for studies, the best at this time in world are:
1. U. S. A.
2. GERMANY
3. CANADA
4. AUSTRALIA
5. SWEDEN.