Question

a and c

following questions concerning this experime fem 3 Consider the photoelectric effect experiment she men shown below. Answer the ev ( I n coming this experiment. The metal plate has a workfunction of Vacuum tube Photon Electron Metal Plate of a current to be measured by the ammeter. E D . i.) Briefly explain why this is the case, ii) Given that this is true would a photon of wavelength 1300 nm cause a current to be measured) Show the calculation to justify your answer. (10 points) c. If the incoming photon energy is 7.0 eV, what is the maximum energy in electron volts of the photoelectrons these photons would produce in this same apparatus? (5 pts.)

Answer 1

a) Wook function define as minimum energy require just to escape an election from metal surface if Ephoton <& (work function) then election is not able to escape hence no current if Ephatan & then electron escape henc current Eust (ii) Ephoton = hc - 1.24 dlum) - 1240 d (nm) - 1240 eu 1300 Ephulon = 0.95eu as Ephoton <Q (=4,7V) Hence cwant not measure b) Ephoton = 7eu & - 4.7V :: maximum Energy in Ep - Q electron 27-4.7 = 2.3 eV