Hello,
Yes. You can do. But many universities will not allow you. However there are some universities where you can get admission for M.Sc Biotechnology after completion of B.Sc in Physics.
You need to appear for the Entrance Exam to get admission for this course.
Each and every university will conduct its own Entrance Exam to give admission for the candidates for this course.
But I don't think its a good career choice for you.
Having completed B.Sc in Physics, you might not be having Biotechnology as one of the subject.
Without having previous subject knowledge, even if you opt for M.Sc Biotechnology, it will be difficult for you to understand the subject and the terminology.
In addition, the boom for Biotechnology is not good in India.
But if you are very much interested to join this course, you can join that.
Wish you all the best.