system
Given the following post, respond as if you're commenting on Reddit:
human
Why is the energy of an EM wave dependent on its frequency, even though the energy of a classical (mechanical) wave is depended on its amplitude?
gpt
The frequency dependence that you mentioned is the energy of a single photon, E=h*v* . The *total* energy associated with the EM field in, say, a certain region of space, or incident on a surface in unit time is determined by the number of photons, as well as the energy of each individual photon.

The number of photons is proportional to the amplitude of the wave, and this is what people mean when they speak of quantized fields.