A 3.0-nC point charge is located at the origin in the xy-plane.
(a) What is the magnitude of the electric field at the coordinates (0.28 m, 0.22 m)?
(b) If a second point charge of ?3.0 nC is placed at the location where you calculated the electric field in part (a), what will be the magnitude of the force on this second charge due to the field of the first?