A pendulum is hung from the negatively charged plate of a capacitor. the pendulum consists ofa small non-conducting sphere of mass 'm' and charge 'q' and an ins

A pendulum is hung from the negatively charged plate of a capacitor. The pendulum consists ofa small non-conducting sphere of mass 'm' and charge 'q' and an insulating thread of length /'. Ifa uniform electric field E is set up between the plates, the time period T of the pendulum is a) T= 2rml / qE c) T-2e-qEim) b) T= 2rlg d) T-2 +qEIm)