(Solved): Two large, thin, charged plastic circular plates each of radius R are placed a short distance s ap ...

Two large, thin, charged plastic circular plates each of radius $$R$$ are placed a short distance $$s$$ apart; $$s$$ is much smaller than the dimensions of a plate. The right-hand plate has a positive charge of $$+Q$$ evenly distributed over its inner surface (Q is a positive number). The left-hand plate has a negative charge of $$?2Q$$ evenly distributed over its inner surface. A very thin plastic spherical shell of radius $$r$$ is placed midway between the plates (and shown in cross section). It has a uniformly distributed positive charge of $$+q$$. You can ignore the contributions to the electric field due to the polarization of the thin plastic shell and the thin plastic plates. Without the plastic sphere, the electric field at $$A$$ would be Ia) the same Ib) smaller Ic) larger Rank the electric field magnitudes at A,B and $$\mathrm{C}$$. IIa) $$E_A>E_B>E_C$$ IIb) $$E_C>E_B>E_A$$ IIc) $$E_B>E_C>E_A$$