Hello,

You have to pursue academic qualification in Bachelor of Science on any other related subject only . Physical Sciences – Candidate needs a degree of M.Sc. in Physics   or any other equivalent degree.or BS-MS in Physical Sciences.

After getting registered/enrolled for PhD/Integrated PhD program within the validity period of two years, Candidates having a bachelor's degree are eligible for CSIR fellowship.

Atleast 55% marks is needed for the exam.

You can go through the link for more details

https://www.google.com/url?sa=t&source=web&rct=j&url=https://competition.careers360.com/articles/csir-ugc-net-eligibility-criteria/amp&ved=2ahUKEwiR0M3n3P30AhUe4jgGHdg8D7UQFnoECDEQAQ&usg=AOvVaw1JND5_U1ZybUJgn8D2xDpk

Hope this is helpful

Thanks