What role did Einstein's explanation of the photoelectric effect play in the development of the particle-wave interpretation of the nature of electromagnetic radiation?

Answer 1

Very interesting platform to discuss about the great transition of thinking about the secrets of nature.

Have we ever seen that when two waves cross each other they collide and get scattered?

If two marbles collide, then they would be scattered. But if two waves cross ie collide, is that possible for one wave to kick the other to go back?

Same way is that possible for water ripples ie wave traversing on the water surface to kick a piece of paper on the surface of water?

If it is not possible then how can light waves falling on a metallic surface to kick electrons (material particle) right from the surface?

So Einstein thought, following Max Planck's quantum theory, light waves have to be in small packets (quanta) and named them as PHOTONS.

So particle nature of waves have come into the realm of science. This has led to think reciprocate. That is, why can't a particle behave as a wave? Hence matter waves suggested by de Broglie came into reality. But the particle has to be in motion relative to the observer.

With all these, one thing is vivid clear. That is, observer is the most important who observes this whole relative phenomena. But the question comes to the mind as "Who is the observer?"

Answer 2

Einstein's explanation of the photoelectric effect showed that light behaves as discrete packets of energy called photons, supporting the particle nature of light. This contributed to the development of the particle-wave duality concept, suggesting that electromagnetic radiation can exhibit both particle-like and wave-like properties.