Photons with a wavelength of 400 nm are incident on an unknown metal, and electrons are ejected from the metal. However, when photons with a wavelength of 700 nm are incident on the metal, no electrons are ejected.
(a) Could this metal be cesium with a work function of 1.8 eV?
(b) Could this metal be tungsten with a work function of 4.6 eV?
(c) Calculate the maximum kinetic energy of the ejected electrons for each possible metal when 200-nm photons are incident on it.