When a monochromatic light hits a surface there are two possible scenarios. First energy of the light is greater or equal to work function and second energy of light is smaller than work function. In the second case if the electron can't be emitted from the metal surface where the energy of the photon goes ? Also why a type of light with energy less than work function cant cause electron emission ? If electrons are in specific states in metal surface then shoulnd't more and more photons hitting the surface will cause the electron to higher states and sometime an electron will be emitted ?