A ring of radius \( R \) carries a uniformly distributed charge \( +Q \). A point charge \( -q \...

A ring of radius \( R \) carries a uniformly distributed charge \( +Q \). A point charge \( -q \) is placed on the axis of the ring at a
\( \mathrm{P} \) distance \( 2 R \) from the centre of the ring and released from rest.

W The particle executes a simple harmonic motion along the axis of the ring.