I need to get this understanding right once and for all. Because of what the photoelectric effect demonstrated, photon energy was seen as proportional to their frequencies (not amplitudes). When shining a light with higher frequency on a metal surface, it would eject an electron whereas a light with a lower frequency could have been unable to. Now, when considering the intensity of light however, isn't that value proportional to the amplitude of the light? I chose choice A due to the nature of the question, but I have trouble swallowing Kaplan's notion that light intensity is proportional to frequency.
Because I'm thinking the the brightness of a light comes from the additive nature of multiple photon waveforms, it is not necessarily proportional to the energy of the individual photon (frequency), but rather the amplitude of each individual photon * number of photons would equal the amplitude of the "light" in its entirety (if each photon were constructively added together).
Anything would be appreciated to help understand this concept.
Perhaps I do not have a full understanding of what constitutes a wave vs. particle, and how each of these two would fundamentally behave.