For a photoelectric tube, calculate the voltage which will be just sufficient to stop electrons emitted by the sodium photo-plate reaching the collector plate when light of frequency 6 x 1014Hz is incident on a sodium plate. Addition information: 1 e = 1.6 x 10-19C Plank's Constant, h = 6.64 x 10-34 Work function, Wo, of sodium = 2.2 x 10-19J