A Feynman diagram for photoelectric effect is a graphical representation of the interaction between a photon and an atom. It illustrates the process of a photon being absorbed by an atom and ejecting a bound electron, resulting in the photoelectric effect.
A Feynman diagram for Compton effect shows the scattering of a photon by an electron. It illustrates the conservation of energy and momentum in the process, where the scattered photon has a longer wavelength than the incident photon due to the transfer of energy to the electron.
Yes, a Feynman diagram can be used to explain pair production, where a photon interacts with a nucleus and produces a particle-antiparticle pair. The diagram shows the conservation of energy and momentum, and the resulting particles can be seen as the "legs" of the diagram.
Feynman diagrams for different processes are related by the fundamental interactions between particles. For example, the photoelectric effect and Compton effect are both electromagnetic interactions, while pair production is a result of the strong interaction between particles.
Yes, Feynman diagrams are still widely used in modern physics as a tool for understanding and calculating particle interactions. They provide a visual representation of complex processes and help to simplify calculations in quantum field theory.