{1} = 2.3eV and a rubidium plate (Rb) with The limit value work function {2} = 2.09v What is the wavelength (lm) that a photon must have to cause electron photoejection and from the two plates; A photon of wavelength 560 nm is incident on the two plates. What velocities do the photoemitted electrons acquire in each case? Explain, Data: Mass of electron (me): 9.109 * 10 ^ - 31 kg. Speed of light (c): 2.998 * 10 ^ 8 * m x ^ - 1 . Planck's constant (h): 6.626 * 10 ^ - 34 * J . IeV: 1.602 * 10 ^ - 19 J.