Light radiation and particle/wave duality?

If the original system is radially symmetric, then the wavefunction of the emitted photon will be radially symmetric as well. Essentially it will emit the photon in "all directions at once" and assuming the photon never interacts with anything it will maintain this state indefinitely.

If you add the hemispherical absorber (and we presume that the absorber has a little blinking light on it which makes it clear whether or not it has absorbed the photon to an observer) what happens depends on what interpretation of quantum mechanics you believe:

Copenhagen Interpretation: The absorber causes the originally radially symmetric wavefunction of the photon to collapse into state that either impacts or does not impact the absorber. I.e. the direction the photon "went" is picked upon impact or non-impact with the absorber.

Many Worlds Interpretation: The universe splits into two. One in which the photon is absorbed and one in which it is not. How it appears to you depends on which of these universes you end up in.

you would say the wavefunction would go in all directions, 'til the photon is absorbed and the wavefunction collapses.

you can't absorb half a photon, since the photon is the quanta.. you have a 50% chance to absorb the photon

you can't watch the photon along it's path, you cannot know where it's gonna be absorbed until it is absorbed, but the wavefunction should tell you how likely it is to be absorbed in whatever place

definite, the seen easy spectrum is merely the easy we are in a position to work out. Photons and quanta are the source of electromagnetism. Electrons take and launch potential in photons. a extensive occasion of non-seen photons are particle annihilation reactions. Say we've an electron and a positron (anti-electron): while an electron and a positron combine, they annihilate one yet another and what's produced is a pair of gamma ray photons. And all of us comprehend that gamma rays are invisible and are not area of the seen easy spectrum.

one atom can't radiate much. The direction of one photon is pretty random, just like the precise position of each electron is unknown, only according to probabilities