The graph shows the maximum kinetic energy of electrons emitted from a metal as a function of the frequency of the incident light. The work function of the metal is A) 6.0 eV. B) 4.0 eV. C) 2.5 eV. D) 0.4 eV. E) 4 × 10^-19 eV.

Question

Quizplus · Accepted Answer

The work function is the minimum amount of energy needed to remove an electron from the metal surface. In this graph, the x-intercept represents the threshold frequency below which no electrons are emitted. The threshold frequency corresponds to the threshold energy or the work function. 
From the graph, the threshold frequency is approximately f = 6.5 x 10^14 Hz, which corresponds to a threshold energy of about 2.5 eV. Therefore, the work function of the metal is 2.5 eV. 
The other answer choices can be eliminated because they do not correspond to the threshold energy obtained from the graph.

The Graph Shows the Maximum Kinetic Energy of Electrons Emitted