A set of laboratory measurements produced a straight-line relationship between the…
PHYSICS · Multi-part · A Level · Physics · Particles and radiation · Particles and radiation
Problem
A set of laboratory measurements produced a straight-line relationship between the maximum kinetic energy of photoelectrons, expressed in joules, and the frequency of the incident light. The slope of the line is positive and the vertical intercept lies below the horizontal axis.
Answer the following questions about the meaning of specific graphical features in this experiment.
(a) Describe what physical constant is represented by the slope and explain, in words, how the experiment reveals this constant.
(b) The vertical intercept of the line is negative. Explain what property of the photoactive surface this negative intercept represents and how that property is obtained from the graph.
(c) Suppose the intensity of the light is increased while its frequency remains unchanged and greater than the threshold frequency. Explain whether any point on the graph of maximum kinetic energy versus frequency would move, and justify your answer.