In physics, light phenomena are optical, as they belong to this subsection. The effects of this phenomenon are not limited to making objects around people visible. In addition, solar lighting transmits thermal energy in space, as a result of which bodies heat up. Based on this, certain hypotheses were put forward about the nature of this phenomenon.
Energy transfer is carried out by bodies and waves propagating in the medium, thus radiation consists of particles called corpuscles. So Newton called them, after him new researchers appeared who improved this system, were Huygens, Foucault, etc. The electromagnetic theory of light was put forward a little later by Maxwell.
The origins and development of the theory of light
Thanks to the very first hypothesis, Newton formed a corpuscular system, which clearly explainedthe essence of optical phenomena. Various color radiations were described as structural components included in this theory. Interference and diffraction were explained by the Dutch scientist Huygens in the 16th century. This researcher put forward and described the theory of light based on waves. However, all the created systems were not justified, since they did not explain the very essence and basis of optical phenomena. As a result of a long search, the questions of the truth and authenticity of light emissions, as well as their essence and basis, remained unresolved.
A few centuries later, several researchers under the leadership of Foucault, Fresnel began to put forward other hypotheses, due to which the theoretical advantage of waves over corpuscles was revealed. However, this theory also had shortcomings and shortcomings. In fact, this created description suggested the presence of some substance that is in space, due to the fact that the Sun and the Earth are at a far distance from each other. If the light falls freely and passes through these objects, then there are transverse mechanisms in them.
Further formation and improvement of the theory
Based on this entire hypothesis, the prerequisites for creating a new theory about the world ether, which fills bodies and molecules, arose. And taking into account the characteristics of this substance, it must be solid, as a result, scientists came to the conclusion that it has elastic properties. In fact, the ether should influence the globe in space, but this does not happen. Thus, this substance is not justified in any way, except that light radiation flows through it, and ithas hardness. Based on such contradictions, this hypothesis was called into question, meaningless and further research.
Maxwell's Works
The wave properties of light and the electromagnetic theory of light can be said to have become one when Maxwell began his research. In the course of the study, it was found that the propagation speeds of these quantities coincide if they are in a vacuum. As a result of empirical substantiation, Maxwell put forward and proved a hypothesis about the true nature of light, which was successfully confirmed by years and other practices and experience. Thus, in the century before last, an electromagnetic theory of light was created, which is still used today. Later it will be recognized as a classic.
Wave properties of light: electromagnetic theory of light
Based on the new hypothesis, the formula λ=c/ν was derived, which indicates that the length can be found when calculating the frequency. Light emissions are electromagnetic waves, but only if they are perceptible to humans. In addition, they can be called such and are treated with fluctuations from 4 1014 to 7.5 1014 Hz. In this range, the oscillation frequency can vary and the color of the radiation is different, and each segment or interval will have a characteristic and corresponding color for it. As a result, the frequency of the specified value is the wavelength in vacuum.
The calculation shows that the light emission can be from 400 nm to 700 nm (violet andred colors). At the transition, the hue and frequency are preserved and depend on the wavelength, which varies based on the propagation velocity and is specified for a vacuum. Maxwell's electromagnetic theory of light is based on a scientific basis, where radiation exerts pressure on the constituents of the body and directly on it. True, this concept was later tested and proved empirically by Lebedev.
Electromagnetic and quantum theory of light
Emission and distribution of luminous bodies in terms of oscillation frequencies is not consistent with the laws that were derived from the wave hypothesis. Such a statement comes from an analysis of the composition of these mechanisms. The German physicist Planck tried to find an explanation for this result. Later, he came to the conclusion that radiation occurs in the form of certain portions - a quantum, then this mass was called photons.
As a result, the analysis of optical phenomena led to the conclusion that light emission and absorption were explained using mass composition. While those that propagated in the medium were explained by the wave theory. Thus, a new concept is required to fully explore and describe these mechanisms. Moreover, the new system was supposed to explain and combine the various properties of light, that is, corpuscular and wave.
Development of quantum theory
As a result, the works of Bohr, Einstein, Planck were the basis of this improved structure, which was called quantum. To date, this system describes and explainsnot only the classical electromagnetic theory of light, but also other branches of physical knowledge. In essence, the new concept formed the basis of many properties and phenomena occurring in bodies and space, and besides this, it predicted and explained a huge number of situations.
Essentially, the electromagnetic theory of light is briefly described as a phenomenon based on various dominants. For example, corpuscular and wave variables of optics have a connection and are expressed by Planck's formula: ε=ℎν, there are quantum energy, electromagnetic radiation oscillations and their frequency, a constant coefficient that does not change for any phenomena. According to the new theory, an optical system with certain varying mechanisms consists of photons with strength. Thus, the theorem sounds like this: quantum energy is directly proportional to electromagnetic radiation and its frequency fluctuations.
Planck and his writings
Axiom c=νλ, as a result of Planck's formula ε=hc / λ is produced, so it can be concluded that the above phenomenon is the opposite of the wavelength with optical influence in vacuum. Experiments carried out in a closed space showed that as long as a photon exists, it will move at a certain speed and will not be able to slow down its pace. However, it is absorbed by particles of substances that it meets on the way, as a result, an interchange occurs, and it disappears. Unlike protons and neutrons, it has no rest mass.
Electromagnetic waves and theories of light still do not explain the contradictory phenomena,for example, in one system there will be pronounced properties, and in another corpuscular, but, nevertheless, they are all united by radiation. Based on the concept of quantum, existing properties are present in the very nature of optical structure and in general matter. That is, particles have wave properties, and these, in turn, are corpuscular.
Light sources
The foundations of the electromagnetic theory of light are based on the axiom, which says: molecules, atoms of bodies create visible radiation, which is called the source of an optical phenomenon. There is a huge number of objects that produce this mechanism: a lamp, matches, pipes, etc. Moreover, each such thing can be divided into equivalent groups, which are determined by the method of heating the particles that realize the radiation.
Structured lights
The original origin of the glow is due to the excitation of atoms and molecules due to the chaotic movement of particles in the body. This occurs because the temperature is high enough. The radiated energy is increased due to the fact that their internal strength increases and heats up. Such objects belong to the first group of light sources.
The incandescence of atoms and molecules arises on the basis of flying particles of substances, and this is not a minimal accumulation, but a whole stream. The temperature here does not play a special role. This glow is called luminescence. That is, it always occurs due to the fact that the body absorbs external energy caused by electromagnetic radiation, chemicalreaction, protons, neutrons, etc.
And the sources are called luminescent. The definition of the electromagnetic theory of light of this system is as follows: if after the absorption of energy by a body some time passes, measurable by experience, and then it produces radiation not due to temperature indicators, therefore, it belongs to the above group.
Detailed analysis of luminescence
However, such characteristics do not fully describe this group, due to the fact that it has several species. In fact, after absorbing the energy, the bodies remain incandescent, then emit radiation. The excitation time, as a rule, varies and depends on many parameters, often does not exceed several hours. Thus, the heating method can be of several types.
A rarefied gas begins to emit radiation after a direct current has passed through it. This process is called electroluminescence. It is observed in semiconductors and LEDs. This happens in such a way that the passage of current gives the recombination of electrons and holes, due to this mechanism, an optical phenomenon arises. That is, energy is converted from electrical to light, the reverse internal photoelectric effect. Silicon is considered an infrared emitter, while gallium phosphide and silicon carbide realize the visible phenomenon.
Essence of photoluminescence
The body absorbs light, and solids and liquids emit long wavelengths that differ in all respects from the originalphotons. For incandescence, ultraviolet incandescence is used. This excitation method is called photoluminescence. It occurs in the visible part of the spectrum. The radiation is transformed, this fact was proved by the English scientist Stokes in the 18th century and is now an axiomatic rule.
Quantum and electromagnetic theory of light describe the concept of Stokes as follows: a molecule absorbs a portion of radiation, then transfers it to other particles in the process of heat transfer, the remaining energy emits an optical phenomenon. With the formula hν=hν0 – A, it turns out that the luminescence emission frequency is lower than the absorbed frequency, resulting in a longer wavelength.
Time frame for the propagation of an optical phenomenon
The electromagnetic theory of light and the theorem of classical physics indicate the fact that the speed of the indicated quantity is large. After all, it travels the distance from the Sun to the Earth in a few minutes. Many scientists have tried to analyze the straight line of time and how light travels from one distance to another, but they have basically failed to do so.
In fact, the electromagnetic theory of light is based on speed, which is the main constant of physics, but not predictable, but possible. Formulas were created, and after testing it turned out that the propagation and movement of electromagnetic waves depends on the environment. Moreover, this variable is definedthe absolute refractive index of the space where the specified value is located. Light radiation is able to penetrate into any substance, as a result, the magnetic permeability decreases, in view of this, the speed of the optics is determined by the dielectric constant.
