() How does one explain the emission of electrons from a photosensitive surface with the help of Einstein's photoelectric equation? (ii) The work function of the following metals is given : Na = 2.75 eV, K = 2.3 eV, MO = 4.17 eV and Ni 5.15 ev. Which of these metals will not cause photoelectric emission for radiation of wavelength 3300 A from a laser source placed 1 m away from these metals? What happens if the laser source is brought nearer and placed 50 cm away