Photoelectric Effect Having run a photoelectric experiment you find that 591 nm
ID: 1383550 • Letter: P
Question
Photoelectric Effect
Having run a photoelectric experiment you find that 591 nm is the longest wavelength of radiation that can cause electron photoemission from the cathode.
The work function of the cathode metal is 3.363 x 10-19 J.
The stopping voltage V0 is 2.1 volts.
If radiation with wavelength of 111 nm is incident on the same cathode, the KE of the photo-emitted electronics will be 9.08875 eV. If the intensity of the light source is 19 mW/cm2, what will be the current flowing in the external circuit if all photo-emitted electrons are collected?
Explanation / Answer
E_ photon= hc/lambda= (6.626*10^-34 * 3*10^8)/ 111* 10^-9m =0.17*10^-17J
J = e* light intensity/ E_photon= 1.6* 10^-19 * 19/ 0.17*10^-17= 1.78 mA/cm2