Alternate vertices carry charges +q and −q.
Find the magnitude and direction of the electric field at the center of the hexagon.

Given: A regular hexagon has charges at all six vertices.
Alternate vertices carry +q and −q.
Distance from center to each vertex = a
Electric field due to one charge at center:
E_0=\frac{kq}{a^2}Now consider one opposite pair (+q,−q).
The field due to +q is away from charge while field due to −q is towards charge.
Hence both fields act in the same direction.
E_{pair}=2E_0E_{pair}=2\frac{kq}{a^2}Three equal vectors are separated by 120°.
The resultant of three equal vectors separated by 120° is zero.
\therefore \vec{E}_{net}=0\boxed{\vec{E}_{net}=0}
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