The diagram shows a pair of horizontal metal plates. Electrons can be deflected vertically using an electric field between the plates. metal plates [A] Label, on the diagram, the polarity of the metal plates which would cause an electron positioned between the plates to accelerate upwards. [ /1K] [B] Calculate the electric field strength when a negatively charged particle consisting of 106 electrons experience a force of 4.0 x 10-16 N between the plates. /2A]