Hi

I am extremely sorry to tell you dear but if you have not studied Physics in your BSc then you can not go for MSc physics.

This is because,
The basic eligibility criteria for MSc physics is that you should have done BSc physics Hons or you should have studied Physics in all the three years of your bsc.

For example,
the eligibility criteria for MSc Physics in BHU is provided below :-

To be eligible for msc you must have studied under 10 + 2 + 3 pattern and should have done physics honours / should have studied Physics in all the three years of your BSc and should have got at least 50% marks in BSC.

You can check the same at its official page the link is provided below

https://www.bhu.ac.in/Centre/escMSc.htm#:~:text=B.Sc.-,*%20under%20at%20least%2010%2B2%2B3%20pattern%20securing%20a,and%20one%20more%20Science%20subject.&text=Common%20Subjects%3A%20(Course%3A%20M.A.%20%2F%20M .

Thank you