In electromagnetic (EM) radiation, the electric and magnetic fields are perpendicular to each other and to the direction of wave propagation. This relationship is known as the "right-hand rule" or the "cross-product rule" and is a fundamental property of EM waves.
The knowledge about the perpendicular orientation of electric and magnetic fields in EM radiation comes from experimental observations and the theoretical framework provided by Maxwell's equations. James Clerk Maxwell, a physicist, developed a set of equations in the 1860s that describe the behavior of electric and magnetic fields and their interaction. These equations form the foundation of classical electromagnetism and accurately predict the behavior of electromagnetic waves.
Maxwell's equations include the wave equation, which relates the electric field (E) and magnetic field (B) in an electromagnetic wave. From the wave equation, it can be mathematically derived that the electric and magnetic fields are perpendicular to each other and to the direction of wave propagation.
Experimental evidence also supports the perpendicular orientation of electric and magnetic fields in EM radiation. For example, observations of the behavior of polarized light, which is a form of electromagnetic radiation, confirm that the electric and magnetic fields oscillate perpendicular to each other.
In addition to experimental evidence and Maxwell's equations, the wave nature of electromagnetic radiation is further supported by various phenomena such as interference, diffraction, and polarization. These phenomena can be explained based on the understanding that the electric and magnetic fields are perpendicular to each other in EM waves.
Overall, the perpendicular orientation of electric and magnetic fields in electromagnetic radiation is a well-established aspect of classical electromagnetism, supported by both theoretical considerations and experimental observations.