I understand how the energy of an individual photon is $hf$ and how the number of electrons emitted in the photo-electric effect is proportional to the number of photons hitting per unit area.
Hence, my question is that how does this number of photons hitting/passing through relate to the classical amplitude of the electric/magnetic fields of the emergent phenomenon of multiple photons that is the classical light wave/collection of waves.
Any brief overview without incorporating complex Quantum Electrodynamics would be sufficient as I’m seeking for the results of those equations and not necessarily the whole process.
