Two thin rods of length L lie on the x axis. One of them has a charge of -Q uniformly distributed along its length and is positioned between x = -L and x = 0. The other one has a charge of +Q uniformly distributed along its length and is positioned between x = 0 and x = L. Find the electric field produced by the two rods (magnitude and direction) at a point O located on the y axis at y = h.