1 23 Here the electric field is uniform and we are considering a closed
cylindrical surface, with its axis parallel to the uniform field E The total
flux f  through the surface is  f = f1 + f2 + f3, where f1 and f2 represent
the flux through the surfaces 1 and 2 (of circular cross-section) of the
cylinder and f3 is the flux through the curved cylindrical part of the
closed surface