Question

what will happen when a light beam having a frequency equal to threshold frequency of metal will fall on the metal.Will the photo electric effect will be observed??if yes give reason as here (hv-hvo)will be ZERO and NO energy will get transferred to electron and hence no kinetic energy it will get and hence it will not get emmited from the metal atoms.​

Answer 1

yeah ,photo electric effect will observe if you apply electric field because when you give energy equal to threshold then electron will come out and after applying positive potential the electron will move and creats electric current,production of electric current is the proof of photoelectric effect