You can study M.Sc Physics. Most students study M.Sc Physics. You can also study PG in any of the subjects that you studied in your Graduation. You can also study M.SC Ph.D dual degrees also. You can study Geo Physics, M.Sc in Astronomy or Astrophysics. You can write entrance exams like IIT JAM, IISER, TIFR GS, NEST,etc for post graduation programmes in various disciplines. But with biophysics as your specialisation, you can work in X ray crystallography, NMR Spectroscopy fields. You can try for opportunities like Biophysicists, Forensic bio physicist, researcher, medical biophysicist, scientist, nutritional biophysicist and clinical Biophysicists.