Two infinite identical charged sheets (each $+\sigma$) and a charged spherical body of charge density $\rho$ are arranged as shown in the figure. Then the correct relation between the electric fields at A, B, C and D is:
Answer: (C) $\vec E_C \ne \vec E_D;\ \vec E_A > \vec E_B$
Use superposition.
**Sheets**: two identical sheets give zero field between them and $\sigma/\varepsilon_0$ outside, pointing away from the sheets (to the left at C, to the right at D).
**Sphere**: its field points away from its centre and weakens with distance.
- A and B lie between the sheets, so only the sphere contributes; A is nearer to the sphere, so $E_A > E_B$.
- At C and D the sheet fields are equal in size but opposite in direction, and the sphere adds a smaller field at C (far away) than at D (close). So $\vec E_C \ne \vec E_D$, in direction and in magnitude.
Solution by Sreeraj P, M.Sc Physics