Electromagnetic waves can exhibit both particle-like and wave-like behavior, depending on the context in which they are observed. This is one of the fundamental principles of quantum mechanics.
In the classical understanding of electromagnetic waves, such as those described by Maxwell's equations, electromagnetic waves are considered to be purely wave-like phenomena. They are described by oscillating electric and magnetic fields that propagate through space.
However, according to quantum mechanics, electromagnetic waves can also be described as particles known as photons. Photons are quanta or discrete packets of energy associated with electromagnetic radiation. Each photon carries a specific amount of energy proportional to its frequency. The energy of a photon is given by Planck's equation: E = hf, where E is the energy, h is Planck's constant, and f is the frequency of the wave.
In certain experiments and phenomena, such as the photoelectric effect or the behavior of light in certain interactions, the particle nature of electromagnetic waves becomes more apparent. Photons can behave like particles, exhibiting characteristics such as energy quantization, momentum, and interactions with matter on a particle-like basis.
So, while electromagnetic waves are fundamentally described as wave-like phenomena, in the quantum realm, they can also exhibit particle-like behavior as photons. The duality of electromagnetic waves as both particles and waves is one of the key features of quantum mechanics.