1) when light of wavelength 2.08*10^-7m falls on a photosurface, a voltage of 1.40V is required to stop the emitted electrons from reaching the anode. What is the largest wavelength of light that will result in emission of electrons from this photosurface? 2) To determine the work function of given photosurface, light of wavelength 2.3*10^-7 m is directed at the surface and the stopping voltage is recorded. When light of wavelength 1.8*10^-7m large as the previous one. Find the work function.