Answer the following question given this paragraph: 

Light also behaves like a package of energy. It turns out that for light, the energy of the “package” of energy is proportional to its frequency. (For most waves, energy is proportional to wave amplitude, or the height of the wave. ) The mathematical equation that relates the energy (E) of light to its frequency is.


Q: For most waves, energy is proportional to what, a term that describes the height of the wave?


A:
wave amplitude