) light (frequency dispersion), or, the same thing, the dependence of the phase velocity of light in matter on frequency (or wavelength). Experimentally discovered by Newton around 1672, although theoretically well explained much later.

Spatial dispersion is the dependence of the dielectric permittivity tensor of a medium on the wave vector . This dependence causes a number of phenomena called spatial polarization effects.

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Dispersion and spectrum of light

Light dispersion and body color

dispersion of light. Phone colors.

Subtitles

Properties and manifestations

One of the most good examples dispersion - the decomposition of white light as it passes through a prism (Newton's experience). The essence of the phenomenon of dispersion is the difference in the phase velocities of propagation of light rays with different wavelengths in a transparent substance - an optical medium (whereas in vacuum the speed of light is always the same, regardless of the wavelength and hence the color). Usually, the shorter the wavelength of light, the greater the refractive index of the medium for it and the lower the phase velocity of the wave in the medium:

• for red light, the phase velocity of propagation in the medium is maximum, and the degree of refraction is minimum,
• for violet light, the phase velocity of propagation in the medium is minimal, and the degree of refraction is maximum.

However, in some substances (for example, in iodine vapor) the effect of anomalous dispersion is observed, in which blue rays are refracted less than red ones, while other rays are absorbed by the substance and escape observation. Strictly speaking, anomalous dispersion is widespread, for example, it is observed in almost all gases at frequencies near the absorption lines, but in iodine vapor it is quite convenient for observation in the optical range, where they absorb light very strongly.

The dispersion of light made it possible for the first time to quite convincingly show the composite nature of white light.

Augustin Cauchy proposed an empirical formula for approximating the dependence of the refractive index of a medium on the wavelength:

where λ (\displaystyle \lambda )- wavelength in vacuum; a, b, c- constants, the values ​​of which for each material must be determined in the experiment. In most cases, you can restrict yourself to the first two terms of the Cauchy formula. Subsequently, other more accurate, but at the same time more complex, approximation formulas were proposed.

The world around us is filled with millions of different different shades. Due to the properties of light, every object and object around us has specific color perceived by the human eye. The study of light waves and their characteristics has allowed people to take a deeper look at the nature of light and the phenomena associated with it. Let's talk about dispersion today.

The nature of light

From a physical point of view, light is a combination electromagnetic waves With different values length and frequency. The human eye does not perceive any light, but only one whose wavelength ranges from 380 to 760 nm. The rest of the varieties remain invisible to us. These include, for example, infrared and ultraviolet radiation. The famous scientist Isaac Newton imagined light as a directed stream of the smallest particles. And only later it was proved that it is by nature a wave. However, Newton was still partly right. The fact is that light has not only wave, but also corpuscular properties. This is confirmed by the well-known phenomenon of the photoelectric effect. It turns out that the light flux has a dual nature.

Color spectrum

White light accessible to human vision is a combination of several waves, each of which is characterized by a certain frequency and its own photon energy. In accordance with this, it can be decomposed into waves of different colors. Each of them is called monochromatic, and a certain color corresponds to its own range of length, wave frequency and photon energy. In other words, the energy emitted by a substance (or absorbed) is distributed according to the above indicators. This explains the existence of the light spectrum. For example, the green color of the spectrum corresponds to a frequency in the range from 530 to 600 THz, and violet - from 680 to 790 THz.

Each of us has ever seen how the rays shimmer on faceted glassware or, for example, on diamonds. This can be observed due to such a phenomenon as the dispersion of light. This is an effect that reflects the dependence of the refractive index of an object (substance, medium) on the length (frequency) of the light wave that passes through this object. The consequence of this dependence is the decomposition of the beam into a color spectrum, for example, when passing through a prism. The dispersion of light is expressed by the following equation:

where n is the refractive index, ƛ is the frequency, and ƒ is the wavelength. The refractive index increases with increasing frequency and decreasing wavelength. We often observe dispersion in nature. Its most beautiful manifestation is the rainbow, which is formed due to the scattering of the sun's rays when they pass through numerous raindrops.

The first steps towards the discovery of dispersion

As mentioned above, when passing through a prism, the light flux decomposes into a color spectrum, which Isaac Newton studied in sufficient detail in his time. The result of his research was the discovery of the phenomenon of dispersion in 1672. Scientific interest in the properties of light appeared even before our era. The famous Aristotle already then noticed that sunlight can have different shades. The scientist argued that the nature of the color depends on the "amount of darkness" present in the white light. If there is a lot of it, then there is purple, and if not enough, then red. The great thinker also said that the main color of light rays is white.

Studies of Newton's predecessors

The Aristotelian theory of the interaction of darkness and light was not refuted by scientists of the 16th and 17th centuries. Both the Czech researcher Marci and the English physicist Khariot independently conducted experiments with a prism and were firmly convinced that the reason for the appearance of different shades of the spectrum is precisely mixing luminous flux with darkness as it passes through a prism. At first glance, the conclusions of scientists could be called logical. But their experiments were rather superficial, and they could not back them up with additional research. That was until Isaac Newton took over.

Newton's discovery

Thanks to the inquisitive mind of this outstanding scientist, it was proved that white light is not the main one, and that other colors do not arise at all as a result of the interaction of light and darkness in different proportions. Newton refuted these beliefs and showed that white light is composite in its structure, it is formed by all the colors of the light spectrum, called monochromatic. As a result of the passage of a light beam through a prism, a variety of colors is formed due to the decomposition of white light into its constituent wave streams. Such waves with different frequencies and lengths are refracted in the medium in different ways, forming a certain color. Newton set up experiments that are still used in physics. For example, experiments with crossed prisms, using two prisms and a mirror, as well as passing light through prisms and a perforated screen. Now we know that the decomposition of light into the color spectrum occurs due to different speed the passage of waves of different lengths and frequencies through a transparent substance. As a result, some waves leave the prism earlier, others a little later, still others later, and so on. This is how the decomposition of the light flux occurs.

Anomalous dispersion

In the future, physicists of the century before last made another discovery regarding dispersion. The Frenchman Leroux discovered that in some media (in particular, in iodine vapor) the dependence expressing the phenomenon of dispersion is violated. The physicist Kundt, who lived in Germany, took up the study of this issue. For his research, he borrowed one of Newton's methods, namely the experiment using two crossed prisms. The only difference was that instead of one of them, Kundt used a prismatic vessel with a solution of cyanine. It turned out that the refractive index when light passes through such prisms increases rather than decreases, as happened in Newton's experiments with conventional prisms. The German scientist found out that this paradox is observed due to such a phenomenon as the absorption of light by matter. In the experiment described by Kundt, the absorbing medium was a solution of cyanine, and the dispersion of light for such cases was called anomalous. In modern physics, this term is practically not used. Today, the normal dispersion discovered by Newton and the anomalous dispersion discovered later are considered as two phenomena related to the same doctrine and having a common nature.

Low Dispersion Lenses

In photography, light dispersion is considered an undesirable phenomenon. It causes the so-called chromatic aberration, in which colors appear distorted in images. The hues of the photograph do not match the hues of the subject being photographed. This effect becomes especially unpleasant for professional photographers. Due to the dispersion in the photographs, not only the colors are distorted, but the edges are often blurred or, conversely, the appearance of an overly defined border. Global photo equipment manufacturers cope with the consequences of such an optical phenomenon with the help of specially designed low dispersion lenses. The glass from which they are made has an excellent property to equally refract waves with different values ​​of length and frequency. Objectives with low dispersion lenses are called achromats.

Light dispersion

Each of us has ever seen how the rays shimmer on faceted glassware or, for example, on diamonds. This can be observed due to such a phenomenon as the dispersion of light. This is an effect that reflects the dependence of the refractive index of an object (substance, medium) on the length (frequency) of the light wave that passes through this object. The consequence of this dependence is the decomposition of the beam into a color spectrum, for example, when passing through a prism.

The dispersion of light is expressed by the following equation:

where n is the refractive index, ƛ is the frequency, and ƒ is the wavelength. The refractive index increases with increasing frequency and decreasing wavelength. We often observe dispersion in nature.

Its most beautiful manifestation is the rainbow, which is formed due to the scattering of the sun's rays when they pass through numerous raindrops.

History of discovery and research.

In 1665-1667, a plague epidemic raged in England, and the young Isaac Newton decided to take refuge from it in his native Woolsthorpe. Before leaving for the countryside, he acquired glass prisms in order to "experiment with the famous phenomena of colors."

Already in the 1st century new era it was known that when passing through a transparent single crystal with the shape of a hexagonal prism, sunlight decomposes into a colored strip - the spectrum. Even earlier, in the 4th century BC, the ancient Greek scientist Aristotle put forward his theory of colors. He believed that the main one is sunlight (white) light, and all other colors are obtained from it by adding various amounts of dark light to it. This idea of ​​light dominated science until the 17th century, despite the fact that numerous experiments were carried out to decompose sunlight using glass prisms.

Investigating the nature of colors, Newton came up with and performed a whole range of various optical experiments. Some of them, without significant changes in the methodology, are still used in physical laboratories.

The first experiment on dispersion was traditional. Having made a small hole in the window shutter of a darkened room, Newton placed a glass prism in the path of the beam of rays passing through this hole. On the opposite wall, he received an image in the form of a strip of alternating colors. Newton divided the spectrum of sunlight thus obtained into seven colors of the rainbow - red, orange, yellow, green, blue, indigo, violet.

The establishment of precisely the seven primary colors of the spectrum is to a certain extent arbitrary: Newton sought to draw an analogy between the spectrum of sunlight and the musical sound range. If we consider the spectrum without such prejudice, then the band of the spectrum arising due to dispersion breaks up into three main parts - red, yellow-green and blue-violet. The remaining colors occupy relatively narrow areas between these primary ones. In general, the human eye is able to distinguish in the spectrum of sunlight up to 160 different color shades.

In subsequent experiments on dispersion, Newton managed to combine colored rays into white light.

As a result of his research, Newton, in contrast to Aristotle, came to the conclusion that when mixing "whiteness and blackness, no color arises ...". All the colors of the spectrum are contained in the sunlight itself, and the glass prism only separates them, since different colors are refracted differently by glass. Violet rays are most strongly refracted, red ones are weakest.

Subsequently, scientists established the fact that, considering light as a wave, each color should be associated with its own wavelength. It is very important that these wavelengths change continuously, corresponding to various shades each color.

The change in the refractive index of a medium depending on the length of the wave propagating in it is called dispersion (from the Latin verb "scatter"). The refractive index of ordinary glass is close to 1.5 for all wavelengths of visible light.

The experiments of Newton and other scientists showed that with increasing wavelength of light, the refractive index of the studied substances decreases monotonically. However, in 1860, while measuring the refractive index of iodine vapor, the French physicist Leroux discovered that red rays are refracted by this substance more strongly than blue ones. He called this phenomenon anomalous dispersion of light. Subsequently, anomalous dispersion was discovered in many other substances.

In modern physics, both normal and anomalous dispersion of light are explained in a single way. The difference between normal and anomalous dispersion is as follows. Normal dispersion occurs with light rays whose wavelength is far from the region of absorption of waves by a given substance. Anomalous dispersion is observed only in the absorption region.

If you look closely at the dispersion of light, you can find its connection with the penetrating power of electromagnetic radiation. Indeed, the shorter the wavelength electromagnetic radiation, the more chances for radiation to penetrate through matter, in the space between atoms. That is why X-ray and gamma radiation have a very high penetrating power.

Dispersion of light in nature and art

Due to dispersion, one can observe different colors Sveta.

The rainbow, whose colors are caused by dispersion, is one of the key images of culture and art.

Due to the dispersion of light, one can observe the color "play of light" on the facets of a diamond and other transparent faceted objects or materials.

To some extent, iridescent effects are found quite often when light passes through almost any transparent object. In art, they can be specially amplified, emphasized.

The decomposition of light into a spectrum (due to dispersion) during refraction in a prism is a fairly common topic in fine arts. For example, the cover of Pink Floyd's album Dark Side Of The Moon depicts the refraction of light in a prism with decomposition into a spectrum.

The discovery of dispersion has become very significant in the history of science. On the tombstone of the scientist there is an inscription with the following words: Here lies Sir Isaac Newton, a nobleman who ... was the first with a torch of mathematics to explain the movements of the planets, the paths of comets and the tides of the oceans.

He investigated the difference between light rays and the resulting various properties flowers that no one had previously suspected. ... Let mortals rejoice that such an adornment of the human race existed.

The world around us is filled with millions of different shades. Due to the properties of light, every object and object around us has a certain color perceived by human vision. The study of light waves and their characteristics has allowed people to take a deeper look at the nature of light and the phenomena associated with it. Let's talk about dispersion today.

The nature of light

From a physical point of view, light is a combination of electromagnetic waves with different lengths and frequencies. The human eye does not perceive any light, but only one whose wavelength ranges from 380 to 760 nm. The rest of the varieties remain invisible to us. These include, for example, infrared and ultraviolet radiation. The famous scientist Isaac Newton imagined light as a directed stream of the smallest particles. And only later it was proved that it is by nature a wave. However, Newton was still partly right. The fact is that light has not only wave, but also corpuscular ...

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Decomposition of light into a spectrum due to dispersion when passing through a prism (Newton's experiment). This term has other meanings, see Variance.

Dispersion of light (decomposition of light) is a phenomenon due to the dependence absolute indicator refraction of a substance on the frequency (or wavelength) of light (frequency dispersion), or, the same thing, the dependence of the phase velocity of light in a substance on the wavelength (or frequency). Experimentally discovered by Newton around 1672, although theoretically well explained much later.

One of the most illustrative examples of dispersion is the decomposition of white light as it passes through a prism (Newton's experiment). The essence of the phenomenon of dispersion is the unequal speed of propagation of light rays with different wavelengths in a transparent substance - an optical medium (whereas in vacuum the speed of light is always the same, regardless of the wavelength and hence the color). Generally, the higher the frequency of the wave, the higher the refractive index...

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Newton's experiments

The first experiments with the dispersion decomposition of light were made by Newton. He directed an ordinary beam of sunlight at a prism and got what many people see every day today - the prism decomposed the light beam into many different colors - from red to purple. After a series of other experiments with lenses and a prism, Newton concluded that the prism does not change sunlight, but only decomposes it into its components. But how does it work?

The fact is that light has a certain speed. As experience has shown, a light beam consists of many colors, so their speed is just different. That is, each color of the spectrum has its own speed of movement and its own wavelength. The degree of refraction of color rays also turned out to be different. Remember what it looks like...

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Chapter 1. Light waves - Lesson 5. Light dispersion
Back to index
Lesson 5. LIGHT DISPERSION

The refractive index does not depend on the angle of incidence of the light beam, but it does depend on its color. It was discovered by Newton.

Making improvements to telescopes. Newton took notice. that the image given by the lens is colored around the edges. He became interested in this and was the first to "investigate the diversity of light rays and the resulting features of colors that no one had even suspected before" (words from the inscription on tombstone Newton). The iridescent coloration of the image given by the lens was observed, of course, before it. It has also been observed that iridescent edges have objects viewed through a prism. A beam of light rays passing through a prism is colored at the edges.

Newton's basic experiment was ingeniously simple. Newton guessed to send a light beam of small cross section to a prism. A beam of sunlight passed into the darkened...

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Gymnasium No. 26 LIGHT DISPERSION Completed by: student 11 B class Shelepov Dmitry Head: Pylkova L.V. Tomsk-2011 In the 17th century, the idea of ​​the wave nature of light began to develop. The first discovery testifying to the wave nature of light was made by the Italian scientist Francesco Grimaldi. He noticed that if an object is placed in the path of a very narrow beam of light, then a sharp shadow does not appear on the screen. The edges of the shadow are blurred, and colored stripes appear along the shadow. Grimaldi called the discovered phenomenon diffraction, but he failed to explain correctly. He understood that the phenomenon he observed was in conflict with the corpuscular theory of light, but he did not dare to completely abandon this theory. Correct explanation open phenomenon associated with the theory of color vision, the foundations of which were laid by the remarkable English scientist Isaac Newton. Light dispersion (decomposition of light) is a phenomenon of the dependence of the absolute refractive index of a substance on the wavelength of light ...

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Dispersion of light (decomposition of light) is the phenomenon of the dependence of the absolute refractive index of a substance on the wavelength of light (frequency dispersion), and also, on the coordinate (spatial dispersion), or, equivalently, the dependence of the phase velocity of light in a substance on the length waves (or frequencies). Experimentally discovered by Newton around 1672, although theoretically well explained much later.

One of the most illustrative examples of dispersion is the decomposition of white light as it passes through a prism (Newton's experiment). The essence of the phenomenon of dispersion is the unequal speed of propagation of light rays with different wavelengths in a transparent substance - an optical medium (whereas in vacuum the speed of light is always the same, regardless of the wavelength and hence the color). Usually, the higher the frequency of the wave, the higher the refractive index of the medium and the lower its speed of light in it:

at the red maximum speed in the medium and the minimum degree of refraction,...

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Physics lesson "Dispersion of light"

Sections: Physics

Lesson objectives:

Educational: introduce the concepts of spectrum, dispersion of light; to acquaint students with the history of the discovery of this phenomenon. visually demonstrate the process of decomposition of a narrow light beam into components of various color shades. identify the differences between these elements of the beam of light. continue the formation of the scientific worldview of students. Developing: the development of attention, figurative and logical thinking, memory in the study of this topic. stimulation of cognitive motivation of students. development of critical thinking. Educational: fostering interest in the subject; fostering a sense of beauty, the beauty of the world.

Type of lesson: lesson of studying and primary consolidation of new knowledge.

Teaching methods: conversation, story, explanation, experiment. (Information-developing)

Requirements to...

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Ministry of Science and Education of Ukraine

Ukrainian Engineering and Pedagogical Academy

Report on the topic:

Light dispersion

Performed by student gr. DRE-S5-1

Fesenko A.V.

Kharkov 2006

dispersion phenomenon

dispersion of light. On a bright sunny day, close the window in the room thick curtain, in which we will make a small hole. Through this hole, a narrow beam of sunlight will penetrate into the room, forming a bright spot on the opposite wall. If you put in the path of the beam

glass prism, then the spot on the wall will turn into a multi-colored strip, in which all the colors of the rainbow will be represented - from purple to red (Fig. 1, f - purple, C - blue, G - blue, 3 - green, G - yellow , O - orange, K - red).

The dispersion of light is the dependence of the refractive index n of a substance on the frequency f (wavelength) of light or the dependence ...

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slide 1
The word "dispersion" comes from the Latin word dispersio, which literally means "scattering, scattering". Light dispersion

slide 2
History of discovery Definition Newton's experience The peculiarity of the passage of a light beam through a prism Main properties Consequences Conditions for the appearance of a rainbow Questions Conclusions Contents

slide 3
The luminous flux, when passing through a prism, is decomposed into a color spectrum, which Isaac Newton studied in sufficient detail in his time. The result of his research was the discovery of the phenomenon of dispersion in 1672. The first steps towards the discovery of dispersion

slide 4
About 300 years ago, Isaac Newton missed Sun rays through the prism. It is not for nothing that on his tombstone, erected in 1731 and decorated with figures of young men who hold in their hands the emblems of his major discoveries, one figure holds a prism, and the inscription on the monument contains the words: “He ...

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Studying the dispersion of light in the 11th grade

The article is categorized under: Teaching physics

This lesson is held at the end of the study of the topic “wave properties of light” in the classes of the physical and mathematical profile.

A. Students should learn:

When falling on the interface between two media, light beams of different colors are refracted in different ways: red - less, and violet - more.

An objective characteristic of color is the frequency of an electromagnetic wave.

B. Students should learn to:

Create the concept of “dispersion of light”.

Recognize the dispersion of light among other phenomena.

Reproduce the dispersion of light in a specific situation.

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11

The dispersion of light is considered as a result of the interaction of electromagnetic waves with charged particles that make up substances. Particles of matter make forced oscillations in the alternating electromagnetic field of the wave.

The dispersion of light is the dependence of the absolute refractive index of a substance n on the frequency ...

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Observation of the phenomenon of light dispersion laboratory
In physics, the dispersion of light is the dependence of the refractive index of a substance on the wavelength of light. The phenomenon of light dispersion is most clearly demonstrated by its decomposition under the action of a prism.

1.3. First experiments with prisms. Ideas about the causes of the appearance of colors before Newton.
1.4. Newton's experiments with prisms. Newton's theory of the origin of colors
1.5. Discovery of anomalous dispersion of light. Kundt's experiments
Chapter II. dispersion in nature
2.1. Rainbow
Chapter III. Experimental setup for observing color mixing
3.1. Installation Description
3.2. Experimental setup device
Conclusion
Literature
Introduction.
dispersion of light. We always encounter this phenomenon in life, but we do not always notice it. But to be careful, the phenomenon of dispersion always surrounds us. One such phenomenon is the common rainbow. There probably isn't a person who doesn't...

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MAOU " secondary school No. 28 named after G. F. Kirdishchev "

Petropavlovsk-Kamchatsky urban district

Dispersion of light and body colors

Synopsis of a physics lesson in grade 11

Lesson of learning new material, consolidation and control

Physics teacher of MAOU "Secondary school No. 28 named after G. F. Kirdishchev" Yuryeva O. L.

Sergey Yesenin

I do not regret, do not call, do not cry,
Everything will pass like smoke from white apple trees.
Withering gold embraced,
I won't be young anymore.

Now you won't fight so much
Cold touched heart
And the country of birch chintz
Not tempted to wander around barefoot.

Wandering spirit! you are less and less
You stir the flame of your mouth
Oh my lost freshness
A riot of eyes and a flood of feelings!

Now I have become more stingy in desires,
My life, or did you dream of me?
Like I'm a spring echoing early
Ride on a pink horse.

All of us, all of us in this world are perishable,
Quietly flowing...

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14

What waves are called coherent?

waves that have the same frequency

waves that have the same amplitude

waves having the same frequency and constant phase difference

The polarization of light proves that light is
flux of neutral particles
transverse wave
longitudinal waves

What is diffraction of light?
splitting white light into a spectrum using a glass prism
amplification or attenuation of light when two coherent waves are superimposed
light avoidance of obstacles

The colors of the spectrum (red - k, orange - o, blue - s, yellow - g, cyan - g, green - h, violet - f) in order of decreasing wavelength are correctly indicated in the answer:
1.f, s, d, s, f, o, k
k, o, f, s, g, s, f
f, g, z, s, f, o, k

The iridescent coloration of thin films of petroleum products in puddles is caused by the phenomenon
diffraction
dispersion
interference

Enlightenment of lenses is explained by ...

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Abstract: Theme of the lesson: “Light is a stream of particles”
Teacher Pylkova L.V., MOU gymnasium No. 26

Lesson topic: "Light is a stream of particles"

Lesson Type: Modified Debate

The organization of "modified" debates allows some changes in the rules, it is possible to increase or decrease the number of players in teams; questions from the audience are allowed, support groups are organized that teams can contact during the game, a group of experts performs the functions of refereeing, develops a compromise solution when it is necessary to achieve educational goals. The main stages of the organization of the educational process based on the use of the debate methodology are: orientation (selection of a topic); preparation for the event; holding debates; game discussion.

^ Lesson objectives:

Generalization and systematization of knowledge

Beam of light passing through triangular prism, deviates to the face opposite the refractive angle of the prism. However, if it is a beam of precisely white light, then after it passes through the prism, it will not only be deflected, but also decomposed into colored beams. This phenomenon is called light dispersion. It was first studied in a series of remarkable experiments.

The source of light in Newton's experiments was a small round hole located in the shutter of a window illuminated by the rays of the Sun. When a prism was placed in front of the hole, instead of a round spot, a colored strip appeared on the wall, called Newton's spectrum. Such a spectrum consists of seven main colors: red, orange, yellow, green, blue, indigo and violet, which gradually passed one into another. Each of them occupies space in the spectrum different size. The purple stripe is the longest and the red stripe the shortest.

The next experiment consisted in the fact that from a wide beam of colored rays obtained with the help of a prism, narrow beams of a certain color stood out by a screen with a small hole and were directed to a second prism.

The prism deflecting them does not change the color of these rays. Such rays are called simple or monochromatic (one-color).

Experience shows that red rays feel less deflection than violet ones, i.e. Rays of different colors are refracted differently by a prism.

Collecting beams of rays that emerged from the prism, Newton received on a white screen instead of a colored stripe a white image of a hole.

From all the experiments carried out, Newton drew the following conclusions:

• white light is inherently complex light, which consists of colored rays;
• rays of light of different colors also have different refractive indices of the substance; as a result, when a beam of white light is deflected by a prism, it decomposes into a spectrum;
• if you combine the colored rays of the spectrum, then again you get white light.

Thus, the dispersion of light is a phenomenon that is due to the dependence of a substance on the wavelength (or frequency).

The dispersion of light is noted not only when light passes through a prism, but also in various other cases of light refraction. So, in particular, the refraction of sunlight in water drops is accompanied by its decomposition into multi-colored rays, this explains the formation of a rainbow.

To obtain the spectrum, Newton directed a rather wide cylindrical beam of sunlight through a round hole made in the shutter onto a prism.

The spectrum obtained in this way is a series of multi-colored images of a round hole, partially superimposed on each other. To obtain a purer spectrum, when studying such a phenomenon as light dispersion, Newton suggested using not a round hole, but a narrow slot parallel to the refracting edge of the prism. Using a lens, a clear image of the slit is obtained on the screen, after which a prism is installed behind the lens, which gives the spectrum.

The purest and brightest spectra are obtained using special instruments - spectroscopes and spectrographs.

Light absorption is a phenomenon in which the energy of a light wave decreases as it passes through a substance. This is due to the transformation of the energy of a wave of light into the energy of secondary radiation, or, in other words, a substance that has a different spectral composition and other directions of propagation.

The absorption of light can cause heating of a substance, ionization or excitation of molecules or atoms, photochemical reactions, and other processes in a substance.