Q. A point source of monochromatic light of 1.0m.W is placed at a distance of 5.0 m from a metal surface. Light falls perpendicularly on the surface. Assume wave theory of light to hold and also that all the light falling on the circular area with radius = 1.0 x ${10}^{-9}$ m (which is few times the diameter of an atom) is absorbed by a single electron on the surface. Calculate the time required by the electron on the surface. Calculate the time required by the electron to receive sufficient energy to come out of the metal if the work function of the metal is 2.0 eV.