Radiant energy and electromagnetic radiation are two terms that refer to the same concept. Both refer to the propagation of energy through space in the form of waves. These waves appear as oscillating electric and magnetic fields, the fundamental feature of electromagnetic radiation.
- Electromagnetic radiation can be viewed as either electromagnetic waves or a stream of photons. These two perspectives are not mutually exclusive but rather complementary, as explained by the concept of wave-particle duality.
- Wave Perspective: From this viewpoint, electromagnetic radiation is thought of as waves of oscillating electric and magnetic fields traversing through space. The energy of the radiation is distributed across the wave, with its intensity related to the amplitude and frequency of the wave.
- Photon Perspective: Electromagnetic radiation can also be thought of as a succession of massless particles known as photons. Each photon carries a discrete quantum of energy, referred to as photon energy, directly related to the radiation’s frequency. This perspective acknowledges the particle-like behaviour of electromagnetic radiation.
- The concept of wave-particle duality which has been developed in Quantum Field Theory, reconciles these contrasting viewpoints by claiming that electromagnetic radiation exhibits both wave-like and particle-like attributes. This duality has been experimentally verified.