



In the photoelectric effect, the number of emitted photoelectrons is dependent on the frequency of the incident light. Below a certain threshold frequency, the light does not have enough energy to emit any photoelectrons, leading to a zero number of emitted electrons. Once the threshold frequency is exceeded, the number of emitted photoelectrons increases.
Thus, the correct plot is option (D), which corresponds to the behavior of the photoelectric effect

The figures below show:
Which of the following points in Figure 2 most accurately represents the nodal surface shown in Figure 1?
The wavelength of spectral line obtained in the spectrum of Li$^{2+}$ ion, when the transition takes place between two levels whose sum is 4 and difference is 2, is