M.Sc

Well, this totally depends on what the college says. But in general, you can opt for M.Sc physics or chemistry after doing your Bachelors in computer science provided that you did well in physics and maths for M.Sc physics and chemistry for M.Sc chemistry. That means, if you were not having chemistry subject while doing your Bachelors in computer science then you are not eligible for M.Sc chemistry. Similarly, if you were not having the physics and maths subjects then you are not eligible for M.Sc physics. Moreover, if you had those subjects doesn't confirm your eligibility, as you must score good in those subjects which vary according to the colleges.
Thank you and best of luck.