Two metal plates 4 cm long are held horizontally 3 cm apart in a vacuum, one being vertically above other. The upper plate is at a potential of 3000 & the lower is earthed. Electrons having a velocity of 1×10^7 m/s are injected horizontally midway between the plates & in the direction parallel to 4 cm edge. Calculate the vertical deflection of the electron beams as it emerges from the plates. (Assume “e/m=1.8×10^11 c/kg”).