The electric field E1 at one face of a parallelepiped is uniform over the entire face and is directed out of the face. At the opposite face, the electric field E2 is also uniform over the entire face and is directed into that face (as shown in figure). The two faces in question are inclined at 30∘ from the horizontal, E1 and E2 (both horizontal) have magnitudes of 2.50×104NC−1 and 7.00×104NC−1, respectively. Assuming that no other electric field lines cross the surfaces of the parallelepiped, the net charge contained within is
