hi!

You can very well join DRDO after doing your B.Sc in physical science with chemistry

Apply for CEPTAM under your relevant Post Code and Subject, prepare for the examination, get through and join DRDO as a Senior Technical Assistant-B.

There are several sub branches of DRDO like Defence institute of bioenergy Research which also have undergraduates as their JRF and several Msc/Mtech students as SRF or other research fellow.