Question

What is stopping voltage (or cut voltage)? Plot a graph of variation of photoelectric current with collector plate potential for two incident radiations of same frequency and different intensities.

Answer 1

Photoelectrons are emitted from a metal, when illuminated with light, above the threshold frequency of the metal, with a range of kinetic energies. The stopping potential is the voltage between the metal surface and a cathode, placed close to the surface, in a vacuum, which just stops them from producing a current.