$\mathrm{ABC}$ is an equilateral triangle. Charges $+\mathrm{q}$ are placed at each corner as shown in fig.…
$\mathrm{ABC}$ is an equilateral triangle. Charges $+\mathrm{q}$ are placed at each corner as shown in fig. The electric intensity at centre $O$ will be
Unit positive charge at $\mathrm{O}$ will be repelled equally by three charges at the three corners of triangle. By symmetry, resultant $\mathrm{E}$ at $\mathrm{O}$ would be zero.
^