In fig. a plastic rod in the form of circular are with charge +Q unformly distributed on it produces an electric fieldof magnitude E at the centre of curvature (at the origin). In fig., more circular rods with identical umform charges +Q are addes until the circle is complete. A fifth arrangement (which would be labeled e) is like taht in d except that the roed in the fourth quadrant has charge-Q. Rank all the five arrangements according to the magnitudes of the electric field at the center of curvature, greatest first.

Explanation

Make use of symmetry property.
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It is clear from diagrams that order of fields will be first): (e ),(b), (a,c),(d),(2E, sqrt(2)E, and zero, repectively).