1. The problem statement, all variables and given/known data If an electron in metallic cesium absorbs a photon of red light (6.6x10^-7) m in vacuum), all the energy is used up in escaping from the attractive forces in the metal. Suppose light with 5x10^-7 is used, what percentage of the photon's energy does the electron retain after it has escaped from the metal? What color light is this? 2. Relevant equations 3. The attempt at a solution I believe the light color would be that of Blue-Green.