Light propagates in waves because it is an electromagnetic wave. According to the electromagnetic wave theory, light is composed of electric and magnetic fields that oscillate perpendicular to each other and propagate through space. This wave-like behavior of light can be explained by Maxwell's equations, which describe the fundamental principles of electromagnetism.
Maxwell's equations indicate that changing electric fields create magnetic fields, and changing magnetic fields create electric fields. This interplay between electric and magnetic fields generates a self-propagating wave known as an electromagnetic wave. Light is a specific type of electromagnetic wave that falls within the visible spectrum, but there are also other types of electromagnetic waves such as radio waves, microwaves, infrared, ultraviolet, X-rays, and gamma rays.
The wave nature of light can be observed through various phenomena, including interference, diffraction, and polarization. These behaviors are characteristic of waves and demonstrate that light exhibits wave-like properties. For example, interference occurs when two or more light waves combine, leading to constructive or destructive interference patterns. Diffraction refers to the bending and spreading of light waves as they encounter obstacles or pass through narrow openings. Polarization involves the alignment of light waves along a specific plane, similar to the orientation of waves on the surface of water.
In summary, light propagates in waves because it is an electromagnetic wave, and its wave-like nature can be explained by Maxwell's equations and observed through various phenomena.