The requirement of percentage may vary college to college and different admission process. So can you specify for which college you want to know?

The scope in forensic science is vast and the options are there in government and private sectors.

After a proper degree in this field, you can open your own forensic practice & forensic service offices. You also may employ in Forensic Laboratories, Detective Offices, Banks and other Govt. and private agencies. The scope is not only in India but also in abroad. SO if you are passionate about this field then only get into this or else you will be left in the midway.