d. 10 10 +4 10 Qnet == 10 2net = 10 15 10 enet= e. 10 Onet = 10 10 10 enet = f. Qnet = 10 For examples a to f, does the surface enclose a net +ve charge, a net-ve charge or no net charge? The figures above show cross sections of three-dimensional closed surfaces. They have flat top and bottom surfaces above and below the plane of the page, respectively. The electric field lines are all parallel to the plane of the page, so that there is no electric flux passing through the top and bottom surfaces. The electric field is uniform over the face of each surface and its strength is indicated in NC-1. 10 10 10