The same ultraviolet beam of wavelength nm is split and sent into two identical…
PHYSICS · Multi-part · Fermi University Physics · Quantum Mechanics · Origins of quantum theory · Origins of quantum theory
Quantum Mechanics: From the Photon to the Hydrogen Atom, Ch Light in lumps: blackbody radiation, the photoelectric effect and Compton scattering
Problem
The same ultraviolet beam of wavelength 210 nm is split and sent into two identical evacuated photocells, one with a clean cobalt cathode (W=5.00 eV) and one with a clean manganese cathode (W=4.10 eV). In each cell the retarding potential is raised until the photocurrent just falls to zero. Take hc=1240 eV nm; contact potential differences are ignored.
((a)) Predict the stopping potential of the cobalt cell.
((b)) Predict the stopping potential of the manganese cell.
((c)) Predict the difference between the two stopping potentials, and say what feature of the light it does not depend on.