A clean sodium surface is illuminated with monochromatic light of various frequencies
PHYSICS · Multi-part · CBSE · Physics · Dual Nature of Radiation and Matter · Dual Nature of Radiation and Matter
Problem
A clean sodium surface is illuminated with monochromatic light of various frequencies. The stopping potentials Vs required to halt the emitted photoelectrons are measured as follows:
Frequency f(1014Hz) : 4.6 5.0 5.4 5.8
Stopping potential Vs(V) : 0.2 0.8 1.3 1.9
(a) Describe how you would graph these data to reveal any linear relationship between stopping potential and frequency. Indicate which quantity should be placed on each axis.
(b) Using the data, estimate (i) the threshold frequency for sodium and (ii) the constant of proportionality that relates Vs to f in the linear region.
(c) Explain why a purely wave description of light that ties energy delivery only to intensity cannot account for the existence of the threshold frequency identified in part (b).
(d) Discuss whether the photoelectric effect, as illustrated by these data, supports a wave description, a particle description, or a dual description of light. Provide two specific pieces of evidence to support your conclusion.