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Light is called an 'electromagnetic wave' for historical reasons* in the following sense: It turned out that the effects of visible light and other radiation can be calculated using Maxwell's equations, which are also used to model the behaviour of electrically charged particles. This was an instant of a successful unification and it hasn't been dismissed since.
- electromagnetic radiation
However when light hits a transparent object at a angle it...
- electromagnetic radiation
- Overview
- Light as electromagnetic radiation
- Electric and magnetic fields
- Maxwell’s equations
In spite of theoretical and experimental advances in the first half of the 19th century that established the wave properties of light, the nature of light was not yet revealed—the identity of the wave oscillations remained a mystery. This situation dramatically changed in the 1860s when the Scottish physicist James Clerk Maxwell, in a watershed the...
In spite of theoretical and experimental advances in the first half of the 19th century that established the wave properties of light, the nature of light was not yet revealed—the identity of the wave oscillations remained a mystery. This situation dramatically changed in the 1860s when the Scottish physicist James Clerk Maxwell, in a watershed the...
The subjects of electricity and magnetism were well developed by the time Maxwell began his synthesizing work. English physician William Gilbert initiated the careful study of magnetic phenomena in the late 16th century. In the late 1700s an understanding of electric phenomena was pioneered by Benjamin Franklin, Charles-Augustin de Coulomb, and others. Siméon-Denis Poisson, Pierre-Simon Laplace, and Carl Friedrich Gauss developed powerful mathematical descriptions of electrostatics and magnetostatics that stand to the present time. The first connection between electric and magnetic effects was discovered by Danish physicist Hans Christian Ørsted in 1820 when he found that electric currents produce magnetic forces. Soon after, French physicist André-Marie Ampère developed a mathematical formulation (Ampère’s law) relating currents to magnetic effects. In 1831 the great English experimentalist Michael Faraday discovered electromagnetic induction, in which a moving magnet (more generally, a changing magnetic flux) induces an electric current in a conducting circuit.
Faraday’s conception of electric and magnetic effects laid the groundwork for Maxwell’s equations. Faraday visualized electric charges as producing fields that extend through space and transmit electric and magnetic forces to other distant charges. The notion of electric and magnetic fields is central to the theory of electromagnetism, and so it requires some explanation. A field is used to represent any physical quantity whose value changes from one point in space to another. For example, the temperature of Earth’s atmosphere has a definite value at every point above the surface of Earth; to specify the atmospheric temperature completely thus requires specifying a distribution of numbers—one for each spatial point. The temperature “field” is simply a mathematical accounting of those numbers; it may be expressed as a function of the spatial coordinates. The values of the temperature field can also vary with time; therefore, the field is more generally expressed as a function of spatial coordinates and time: T(x, y, z, t), where T is the temperature field, x, y, and z are the spatial coordinates, and t is the time.
In the early 1860s, Maxwell completed a study of electric and magnetic phenomena. He presented a mathematical formulation in which the values of the electric and magnetic fields at all points in space can be calculated from a knowledge of the sources of the fields. By Faraday’s time, it was known that electric charges are the source of electric fie...
However when light hits a transparent object at a angle it will be refracted (except at 90 degrees). This is a property of a wave. Therefore light is seen as electric waves and magnetic waves oscillating at right angles from each other. Light is always either a wave or a particle but never both at the same time.
In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. [4][5] In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum, and polarization.
Nov 14, 2024 · Light is electromagnetic radiation that can be detected by the human eye. Electromagnetic radiation occurs over an extremely wide range of wavelengths, from gamma rays with wavelengths less than about 1 × 10 −11 metres to radio waves measured in metres.
Apr 8, 2008 · The electromagnetic spectrum describes different types of radiation, from visible light to gamma rays and more. Energy travels throughout the universe at the speed of light as radiation. What that radiation is called depends on its energy level. At the really high-energy end of the spectrum are gamma rays. They’re close cousins to the X-rays ...
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May 13, 2023 · Published: May 13, 2023. Sharing is Caring. According to Huygens, an expanding sphere of light behaves as if each point on the wave front were a new source of radiation with the same frequency and phase as the preceding one. Because electromagnetic waves have fluctuating electric and magnetic fields, they are called electromagnetic waves.
