M.Sc Physics

You should opt for MBA as it has a better scope as compared to M.Sc in physics.

Different universities have different eligibility criteria for their Ph.D program. Please check with the university for admission requirements in their Ph.D program. On an average, the minimum requirement is 60% or 6.00-6.75 CGPA in their M.Sc. program. Please refer to the link mentioned below for a list of colleges which offer Ph.D programs and use the filters on the page to navigate to a program of your choice:
https://www.shiksha.com/humanities-social-sciences/colleges/ph-d-colleges-india

If you want to choose teaching field then pursue B.Ed. Otherwise you may choose any course according to your interest.

Please refer to the link mentioned below for details regarding admissions and other details related to gaining entry in Rajasthan University for M.Sc. physics:
https://www.shiksha.com/university/university-of-rajasthan-jaipur-23071

That depends on the university you are applying to. Few universities have minimum 60% as the cut-off while others have 50% as the cut-off. For eg: DU has 60% as the cut-off, whereas, Manipal has the 50% as the cut-off.

Some of the books which you can refer to are as follows:
1-Introduction to Quantum mechanics by David J Griffith, 2nd edition.
2-Mathematical physics and special relativity by M Das, PK Jena, BK Das.
3-Heat & thermodynamics by DS Mathur.
4-Statistical mechanics by MC Gupta.
5-Classical mechanics by Chattopadhaya.
6-Introduction to electromagnetic theory by Reitz & Milford.
7- Mechanics by S Chand.