The electromagnetic waves vary in size and thus have different wavelengths. The distance between two consecutive troughs or crests is the wavelength. An electromagnetic wave of single frequency generally known as a monochromatic wave contains successive crests and troughs. This fact requires both the fields to be in-phase. This is true for near-field antennas.įor far-field electromagnetic radiation, the time-change in one type of field comes out to be proportional to the space-change in the other type of field. As the fields are sinusoidal functions, this can create a phase difference between the electric and magnetic fields. This is because one is produced by the other. There is a common misconception that both the fields are out of phase. This means that both reach maxima and minima at the same points. The electric and the magnetic fields are in the same phase in a lossless medium. Thus, the strengths of these fields remain in a fixed ratio to satisfy Maxwell’s equations. The Maxwell equations specify the production of magnetic part from the electric part and vice versa. Transverse wave suggests that the direction of energy transfer is perpendicular to the oscillations of the wave. Wave ModelĮlectromagnetic radiation travel in forms of transverse waves in isotropic, homogenous media. Thus the components of the sunlight bend by different amounts and form a spectrum. This is due to the fact that the refractive index of the prism depends on the wavelength of the light wave passing through it. When it passes through a prism, it disperses into a spectrum of visible light. Natural sunlight consists of composite wavelengths. The degree of change in the path is determined by the ratio of the refractive indices of the two media, known as Snell’s law. This results in the alteration of its speed and the direction of the light wave. In media like some crystals, the light and the static magnetic or electric fields interact through Faraday effect and Kerr effect.ĭuring refraction of a light wave, it crosses from one medium to another medium of different density. In the case of non-linear media, there is an occurrence of some interaction. When the electromagnetic field travels through static and magnetic fields in a medium that is linear such as vacuum, they remain unaffected. This resultant irradiance deviates from the sum of the constituent irradiances of the individual overlapping light waves.
When two or more coherent light waves interact, they form a constructive or destructive interference pattern. The magnetic and electric fields are vector fields, thus they follow vector addition. A time-varying electric or magnetic field or a field produced by any specific particle adds to the fields present in the vicinity due to other causes. The principle of superposition is followed by the electric and magnetic fields. There are different names for the electromagnetic waves of varying frequencies depending upon their sources and effects on the surroundings.Įlectromagnetic Radiation Properties of Electromagnetic RadiationĮlectromagnetism is a physical phenomenon which elaborates the theory of electrodynamics. The electromagnetic spectrum characterizes the electromagnetic waves with respect to their frequency of oscillation and sometimes wavelength. If a point source emits electromagnetic waves, its wavefront appears to be a sphere. These fields are perpendicular to each other like a transverse wave. In media that are isotropic and homogenous, the propagation of a wave is perpendicular to the fields. The velocity of the electromagnetic waves is equal to the speed of light c. The electromagnetic waves are oscillations which are synchronized with perpendicular electric and magnetic fields.
Some are microwaves, radio waves, visible light, X-rays, ultraviolet rays, and gamma rays. These waves include different types of waves.
These waves propagate through space and carry electromagnetic radiant energy. Electromagnetic radiation in the field of physics refers to the waves of the electromagnetic field.
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