Four charges are arranged at the corners of a square, as depicted in the figure.
(a) Using the symmetry of the arrangement, determine the direction of the electric field at the center of the square due to the four charges at the corners, given that q a = q b = -3.4 μC and q c = q d = 3.4 μC.
(b) Calculate the magnitude of the electric field, in newtons per coulomb, at the center of the square (the location of q), given that the square is 4.5 cm on a side.
