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Step-by-Step Explanation
Step 1: Understand the System of Charged Plane Sheets
We have two infinite plane sheets intersecting at a right angle (90°). One sheet is positively charged with surface charge density $ \sigma_+ $, and the other is negatively charged with surface charge density $ \sigma_- $. We are also given that the magnitude of the positive surface charge density is greater than that of the negative one, i.e., $|\sigma_+| > |\sigma_-|$.
Step 2: Direction of Electric Field for a Charged Plane
For a positively charged infinite plane sheet, the electric field lines move away from the plane (perpendicular to the plane surface, in both directions if the plane is isolated). For a negatively charged infinite plane sheet, the electric field lines move toward the plane.
Step 3: Superposition of Fields from Both Sheets
When both planes are present simultaneously and are oriented at 90° to each other, the net electric field in any region is the vector sum of the field contributions from each sheet. Because $|\sigma_+|$ is greater than $|\sigma_-|$, the overall “outward” influence of the positive plane will be stronger than the “inward” pull of the negative plane.
Step 4: Visualizing the Resultant Field Lines
1. Near the positively charged sheet ($ \sigma_+ $), field lines emanate outward.
2. Near the negatively charged sheet ($ \sigma_- $), field lines converge inward.
3. Where the sheets intersect at right angles, the electric field lines must reflect the superposition: they bend or curve in such a way that they emerge predominantly outward from the region of stronger positive charge while curving inward toward the negative sheet.
Step 5: Identifying the Correct Diagram
Among the given figures, the one that correctly depicts stronger lines emanating from the positively charged sheet and lines drawn inward to the negative sheet, accounting for the 90° intersection, is:
This figure shows appropriate curvature of the field lines with a dominance of outward lines from the positively charged plane and inward lines toward the negatively charged plane.
Step 6: Reference Solution Diagram
Below is the provided reference solution diagram for additional clarity: