The document discusses several topics in atomic and nuclear physics including:
1) The photoelectric effect describes how light shining on a metal surface can eject electrons. Compton scattering demonstrates that X-rays lose energy when scattered by electrons, showing the particle nature of light.
2) X-rays are produced when high-energy electrons collide with atoms, either ejecting inner electrons or through braking radiation when deflected by the nucleus.
3) Light exhibits both wave and particle properties in experiments like the photoelectric effect, Compton scattering, and the Young's interference experiment, known as wave-particle duality.
4) Electrons falling between energy levels emit photons with energy equal to the level difference