So I've seen this equation used to calculate the energy associated with an electromagnetic wave: E=hf E is energy, h is a constant, and f is frequency. Therefore, the energy is related to frequency alone. However, why wouldn't the amplitude of that wave have an effect on the energy? I don't get it. If you have an extremely intense radio wave that requires much more energy to generate than waves such as your cell phone, why doesn't this equation show the effect of amplitude?