Physics questions about light

[Alex K]

Is this behavior (absorb/emit) particle or wave description? Seems like describing the phenom in the OP as a wave gives the best answer.

The full quantum theoretic description does not, I would say, introduce this dichotomy all that explicitly, but it employs what looks more like a wave picture up until the particles are detected using a position measurement, at which point the distribution of the quantum wave simply gives you the probability distribution of your position measurement for the particle. As soon as this position measurement has passed, the particle, if it still exists, is again described by a wave.

The incoming particles of, say, photon-electron scattering, are described as a two-particle wave of a certain size, details depending on the quantum uncertainty of their initial positions, momenta and whether they are entangled.