How does the photon model explain electromagnetic radiation?

The photon model explains electromagnetic radiation by describing it as granular, consisting of discrete packets of energy called photons. Proposed by Albert Einstein in 1905, this model posits that radiation is not merely a continuous wave but is composed of quanta, each carrying a fixed amount of energy ($E$) determined by the radiation's frequency ($f$):12

$$E=hf$$

In this equation, $h$ represents Planck’s constant. Because $f=c/\lambda$ (where $c$ is the speed of light and $\lambda$ is the wavelength), the energy of a photon is inversely proportional to its wavelength.32

Photons are subatomic particles classified as bosons; they possess no electric charge or rest mass and serve as the carriers of the electromagnetic field. This model successfully explains phenomena that classical wave theory cannot, such as the photoelectric effect, where the emission of electrons depends on the frequency of light rather than its intensity. Additionally, the Compton effect demonstrates the particle-like nature of radiation through the scattering of X-rays as collisions between photons and electrons.132