Four identical charges in a square all have a magnitude of 12 microcoulombs (but some are positive and some negative), and the length of each side is 18 cm.
i. what is the electric field at origin O? (at the center of the square)
ii. calculate the electric field (magnitude and direction) at the midpoint P.
iii. Assume the square has a length of L = 0.235 m on each side and has four charges fixed in place at each corner with equal magnitudes of Q = 2.5 microcoulombs. Then suppose that two are the charges are positive and two are negative. If the center point has a charge of q = 0.50 microcoulombs, what is the net force acting in charge q?