Final answer:
The photoelectric effect in metals provides evidence for the particle nature of EM radiation, as it involves the ejection of electrons when photons with sufficient energy strike a metal surface.
Step-by-step explanation:
One type of evidence for the particle nature of EM radiation is the photoelectric effect in metals. This phenomenon occurs when light strikes a metal surface and electrons are ejected from the metal. The explanation for the photoelectric effect lies in the concept that EM radiation behaves as particles called photons. Each photon has a discrete amount of energy that depends on the frequency of the radiation. If a photon has enough energy, it can knock an electron out of the metal. The photoelectric effect cannot be explained by considering EM radiation solely as a wave; it requires understanding the radiation as having particle-like properties, with photons imparting energy to electrons.
Thus, the correct answer to the question is b) Photoelectric effect in metals. This effect reveals the particle aspect of EM radiation and supports the wave-particle duality, the concept that EM radiation has both wave-like and particle-like properties.