posted by ka .
Three 3.0 microC charges are at the three corners of an square of side 0.50 m. The last corner is occupied by a -3.0 microC charge. Find the electric field at the center of the square
Use the principle of superposition. The E field at the center will be the sum of two cases:
(a) +3 microC at the open corner, and all three other corners
(b) -6 microC at the open corner location only
Case (a) results in a net E field at the center of zero. That leaves you with case (b), which is easily solved.
The total E is zero