B.Sc Physics

I think B.Sc (honors) is a better option.

SRM University, Sonepat is the best college for B.Sc Physics in Delhi NCR. B.Sc - Physics (Hons. )
Duration: 3 years
Fee: INR 50,000/- p. a. The academic-curriculum of the Department is designed to encourage out of the box thinking with intent to provide scientific solutions at par with the requirement of society. The Department is conducting research in the front-line areas of Applied Physics including Nano-photonics, surface-enhanced Raman scattering (SERS) and Raman spectroscopy, microfluidics, biosensors, etc.

The candidates should complete their B.Sc degree under any registered University with Physics, Chemistry, Zoology, Botany, Biochemistry, Microbiology, B. Pharm, BDS or Applied Science. So, yes you can do it MSc in forensic science

https://www.shiksha.com/university/msu-the-maharaja-sayajirao-university-of-baroda-vadodara-37071
Here are complete details of the college along with all the previous cut-off.

The decision would be based on your interest areas and long term career plans. If you want to pursue a career in academics/research/pure Science areas then B.Sc would be a better option. However, if you want to move into the technical/operations/general management side then B.Tech would be better. A B.Sc is a 3-year programme, whereas a B.Tech is a 4 year programme. A B.Tech programme is specialised course & does carry more weightage compared to B.Sc.

For M.Sc maths you will have to do first obtain bsc maths and pass it with the requisite % of marks/cgpa or sgpa.