A clean metallic surface is irradiated with light of various frequencies to study…
PHYSICS · Multi-part · A Level · Physics · Particles and radiation · Particles and radiation
Problem
A clean metallic surface is irradiated with light of various frequencies to study photo-emission.
(i) Define the term threshold frequency for photo-electric emission from a metal.
(ii) Explain, with reason, why increasing the intensity of incident light whose frequency is below the threshold value does not lead to emission of electrons from the surface.
(iii) The threshold wavelength of sodium is 680nm. State the relation between this wavelength and the work function of sodium and briefly justify it on the basis of energy conservation.