B.Sc Maths

Hello Govind,
Yes, you can. Most universities require you to have physics as your extra-departmental/pass course for you to study physics in M.Sc. However, since science departments offer admission to Master's degree students via entrance exams, this might be difficult anyway. You'll have to work hard in physics to crack entrance exams. Alternatively, you could apply for an applied mathematics degree in Calcutta University or CMI or even for M.Sc in mathematics. Most of the departments have someone or the other working in the mathematical physics. Courses that are relevant to that are differential geometry, probability theory/functional analysis, representation theory/Lie groups and of course, the theory of differential equations.
Approaching physics via mathematics is reasonably common.

Hi,
In most of the colleges/universities, the admission process has already begun. My cousin has also applied for the 2017 batch of Thapar University who are also inviting the applications online.
Here's a link to the facebook post from which we got to know about the admission process-
https://www.facebook.com/thaparuniversityofficial/photos/a.759419287411074.1073741832.756051184414551/1473767072642955/?type=3
Here is a link for Thapar University's website- www.thapar.edu and another link you can go for admission reference- http://bit.ly/2niZsVx
TU is one of the best technical university in India and ranks 8th among all universities for its placement record, so I guess this is the best opportunity for you to apply. And, they also have B.Sc courses available.
Hope this helps.