In physics, light phenomena are optical, as they relate to this subsection. The actions of this phenomenon are not limited to the fact that objects around people are noticeable. In addition, solar lighting transmits thermal energy in space, as a result of this, the 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, so radiation consists of particles called corpuscles. That's what 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, where the essence of optical phenomena was clearly explained. Various color radiations were described as structural components that are part of this theory. Interference and diffraction was explained by a scientist from Holland Huygens in the XVI century. This researcher put forward and described the theory of light based on waves. However, all created systems were not justified, since they did not explain the essence and basis of optical phenomena. As a result of a long search, the questions of the truth and authenticity of light radiation, as well as their essence and basis, remained unresolved.
After several centuries, several researchers led by Foucault and Fresnel began to put forward other hypotheses, which revealed the theoretical advantage of waves over corpuscles. However, this theory also had flaws and shortcomings. In fact, this created description assumed the presence of a certain substance that is in space, due to the fact that the Sun and the Earth are at a distant distance from each other. In the event that light freely falls and passes through these objects, therefore, transverse mechanisms are present in them.
Further formation and improvement of the theory
On the basis of this hypothesis, prerequisites arose for the creation of a new theory about the world ether, which fills bodies and molecules. 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 by anything, except that light radiation flows through it, and it has hardness. Based on such contradictions, this hypothesis was called into question, devoid of meaning and further research.
Maxwell Proceedings
The wave properties of light and the electromagnetic theory of light, we can say, became one when Maxwell began his research. In the course of the study, it was found that the propagation velocity of the indicated values 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 has been successfully confirmed for years and other practices and experiences. Thus, in the century before last, the electromagnetic theory of light was created, which is used today. Later it will be recognized as 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 in calculating the frequency. Light radiation is electromagnetic waves, but only if they are tangible to humans. In addition, these can be called and belong to them with a fluctuation from 4 · 10 14 to 7.5 · 10 14 Hz. In this range, the oscillation frequency can vary and the color of the radiation is different, and on each segment or interval there will be a characteristic color corresponding to it. As a result, the frequency of the indicated value is the wavelength in vacuum.
In the calculation, it can be seen that light emission can be from 400 nm to 700 nm (purple and red). During the transition, the hue and frequency are preserved and depend on the wavelength, which changes based on the propagation velocity and is indicated for vacuum. Maxwell's electromagnetic theory of light is based on a scientific justification, where radiation puts pressure on the components of the body and directly on it. True, later this concept was tested and empirically proven by Lebedev.
Electromagnetic and quantum theory of light
The radiation and distribution of luminous bodies according to the frequencies of oscillations is not consistent with the laws that were derived from the wave hypothesis. A similar statement comes from an analysis of the composition of these mechanisms. 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 photons began to call this mass.
As a result, an analysis of optical phenomena led to the conclusion that light emission and absorption were explained using mass composition. While those that circulated in the medium were clarified by wave theory. Thus, in order to fully study and describe these mechanisms, a new concept is required. Moreover, the new system was to explain and combine the various properties of light, that is, corpuscular and wave.
The development of quantum theory
As a result, the works of Bohr, Einstein, and Planck were the basis of this improved structure, which was called quantum. Today, this system describes and explains not only the classical electromagnetic theory of light, but also other sections of physical knowledge. In essence, the new concept formed the basis of many properties and phenomena occurring in bodies and space, and in addition, a huge number of situations predicted and clarified.
Essentially, the electromagnetic theory of light is briefly described as a phenomenon based on various dominants. For example, the corpuscular and wave variables of optics are connected and are expressed by the Planck formula: ε = ν, here 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 force. Thus, the theorem reads as follows: quantum energy is directly proportional to electromagnetic radiation and its frequency oscillations.
Planck and his works
Axiom c = νλ, as a result of the Planck formula ε = hc / λ is produced, so we can conclude that the above phenomenon is the inverse of the wavelength under optical influence in vacuum. The experiments conducted in closed space showed that as long as a photon exists, it will move at a certain speed and cannot slow down its pace. However, it is absorbed by particles of substances that meet him on the way, as a result, interchange takes place, and it disappears. Unlike protons and neutrons, it has no rest mass.
Electromagnetic waves and theories of light still do not explain contradictory phenomena, for example, in one system there will be pronounced properties, and in the other corpuscular, but, nevertheless, they are all united by radiation. Based on the concept of quantum, existing properties are present in the very nature of the optical structure and in general matter. That is, particles have wave properties, and these, in turn, are corpuscular.
Light sources
The fundamentals of the electromagnetic theory of light are based on the axiom that states: molecules, atoms of bodies create visible radiation, which is called the source of the optical phenomenon. There is a huge number of objects producing this mechanism: a lamp, matches, tubes, etc. Moreover, each such thing can be conditionally divided into equivalent groups, which are determined by the method of glowing particles that realize radiation.
Structured light sources
The initial origin of the glow is due to the excitation of atoms and molecules due to the chaotic motion of particles in the body. This occurs because the temperature is high enough. The radiated energy increases due to the fact that their internal strength increases and glows. Such items 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 does not play a special role here. Such a glow is called luminescence. That is, it always arises due to the fact that the body absorbs external energy caused by electromagnetic radiation, a chemical reaction, protons, neutrons, etc.
And the sources are called luminescent. The definition of the electromagnetic theory of light of this system is as follows: if some time elapses after the body absorbs energy, measurable experimentally, 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 the absorption of energy, the bodies are in incandescent, then emit radiation. The excitation time, as a rule, varies and depends on many parameters, often does not exceed several hours. Thus, the glowing method can be of several types.
The rarefied gas begins to emit radiation after direct current has passed through it. Such a process is called electroluminescence. It is observed in semiconductors and LEDs. This happens in such a way that the transmission of current gives a recombination of electrons and holes, due to this mechanism an optical phenomenon occurs. That is, energy is converted from electrical into light, the inverse internal photoelectric effect. Silicon is considered an infrared emitter, and gallium phosphide and silicon carbide realize a visible phenomenon.
The essence of photoluminescence
The body absorbs light, as well as solids and liquids emit long waves, which differ in all respects from the original photons. For glow, ultraviolet glow is used. This method of excitation is called photoluminescence. It occurs in the visible part of the spectrum. Radiation is transformed, it was this fact that was proved by the English scientist Stokes in the XVIII century and is now an axiomatic rule.
The quantum and electromagnetic theory of light describe the Stokes concept 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 = hν 0 - A, it turns out that the luminescence emission frequency is lower than the absorbed frequency, and as a result it turns out that the wavelength is longer.
The 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 this quantity is great. After all, the distance from the Sun to the Earth, it passes in a few minutes. Many scientists have tried to analyze the straight line of time and how light travels through one distance to another, but they basically did not succeed.
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 checking it turned out that the propagation and movement of electromagnetic waves depends on the environment. Moreover, this variable is determined by the absolute refractive index of the space where the specified value is located. Light can penetrate into any substance; as a result, the magnetic permeability decreases, because of this, the speed of the optics is determined by the dielectric constant.