What is radiation? Types of ionizing radiation, units of measurement, effects on the human body

home The realities of our time are such that natural environment

New factors are increasingly invading human habitats. One of which is various types of electromagnetic radiation.

Natural electromagnetic background has always accompanied people. But its artificial component is constantly replenished with new sources. The parameters of each of them differ in the power and nature of the radiation, wavelength, and the degree of impact on health. What radiation is the most dangerous for humans?

How electromagnetic radiation affects humans

Electromagnetic radiation propagates in the air in the form of electromagnetic waves, which are a combination of electric and magnetic fields that change according to a certain law. Depending on the frequency, it is conventionally divided into ranges.

The processes of information transfer within our body are of an electromagnetic nature. The incoming electromagnetic waves introduce misinformation into this mechanism, well-functioning by nature, causing first unhealthy conditions, and then pathological changes according to the principle “where it breaks.” One has hypertension, another has arrhythmia, the third has hormonal imbalance, and so on.

The mechanism of action of radiation on organs and tissues What is the mechanism of action of radiation on human organs and tissues? At frequencies less than 10 Hz, the human body behaves like a conductor. Particularly sensitive to conduction currents nervous system

. The heat transfer mechanism operating in the body copes well with a slight increase in tissue temperature.

High frequency electromagnetic fields are a different matter. Their biological effect is expressed in a noticeable increase in the temperature of irradiated tissues, causing reversible and irreversible changes in the body.

• A person who has received a dose of microwave irradiation exceeding 50 microroentgens per hour may experience disorders at the cellular level:
• stillborn children; disruptions in activity various systems
• body;

acute and chronic diseases.

What range of electromagnetic radiation is the most dangerous? It's not that simple. The process of radiation and absorption of energy occurs in the form of certain portions - quanta. The shorter the wavelength, the more energy its quanta have and the more trouble it can cause once it enters the human body.

The most “energetic” quanta are those of hard X-ray and gamma radiation. The whole insidiousness of short-wave radiation is that we do not feel the radiation itself, but only feel the consequences of their harmful effects, which largely depend on the depth of their penetration into human tissues and organs.

What type of radiation has the greatest penetrating power? Of course, this is radiation with a minimum wavelength, that is:

• x-ray;

It is the quanta of these radiations that have the greatest penetrating power and, most dangerously, they ionize atoms.

As a result, there is a possibility of hereditary mutations, even with low doses of radiation. If we talk about X-rays, then its single doses during medical examinations are very insignificant, and the maximum permissible dose accumulated over a lifetime should not exceed 32 Roentgens. To obtain such a dose it would take hundreds x-rays

, performed at short time intervals.

What can be a source of gamma radiation? As a rule, it occurs during the decay of radioactive elements. The hard part of ultraviolet radiation can not only ionize molecules, but also cause very serious damage to the retina. In general, the human eye is most sensitive to wavelengths corresponding to a light green color. They correspond to waves of 555–565 nm. At dusk, the sensitivity of vision shifts towards shorter blue waves of 500 nm. This is explained big amount

photoreceptors that perceive these wavelengths.

But the most serious damage to the organs of vision is caused by laser radiation in the visible range.

How to reduce the danger of excess radiation in an apartment

And yet, what radiation is the most dangerous for humans? There is no doubt that gamma radiation is very “unfriendly” to to the human body . But lower-frequency electromagnetic waves can also cause harm to health. An emergency or planned power outage disrupts our life and usual work. All the electronic “stuffing” of our apartments becomes useless, and we, having lost the Internet, cellular communication

The entire arsenal of electrical household appliances is, to one degree or another, a source of electromagnetic radiation, which reduces immunity and impairs the functioning of the endocrine system.

A connection has been established between the distance of a person’s place of residence from high-voltage transmission lines and the occurrence of malignant tumors. Including childhood leukemia. These sad facts can be continued indefinitely. It is more important to develop certain skills in their operation:

• when operating most household electrical appliances, try to maintain a distance of 1 to 1.5 meters;
• place them in different parts apartments;
• remember that an electric razor, a harmless blender, a hair dryer, an electric Toothbrush- create a fairly strong electromagnetic field, which is dangerous due to its proximity to the head.

How to check the level of electromagnetic smog in an apartment

For these purposes it would be good to have a special dosimeter.

The radio frequency range has its own safe dose of radiation. For Russia, it is defined as energy flux density, and is measured in W/m² or µW/cm².

1. For frequencies ranging from 3 Hz to 300 kHz, the radiation dose should not exceed 25 W/m².
2. For frequencies ranging from 300 MHz to 30 GHz 10 - 100 µW/cm².

IN various countries The criteria for assessing the danger of radiation, as well as the quantities used to quantify them, may differ.

In the absence of a dosimeter, there is a fairly simple and effective method checking the level of electromagnetic radiation from your household electrical appliances.

1. Turn on all electrical appliances. Approach each of them one by one with a working radio.
2. The level of interference that occurs in it (crackling, squeaking, noise) will tell you which device is the source of stronger electromagnetic radiation.
3. Repeat this manipulation near the walls. The level of interference here will indicate the places most polluted with electromagnetic smog.

Maybe it makes sense to rearrange the furniture? In the modern world, our body is already exposed to excessive poisoning, so any actions to protect against electromagnetic radiation are an indisputable plus for your health.

Radioactive radiation is powerful impact on the human body, capable of causing irreversible processes leading to tragic consequences. Depending on power Radioactive radiation can cause serious illnesses, and can, on the contrary, heal a person. Some of them are used for diagnostic purposes. In other words, everything depends on the controllability of the process, i.e. its intensity and duration of impact on biological tissues.

The essence of the phenomenon

In general, the term radiation refers to the release of particles and their propagation in the form of waves. Radioactivity involves the spontaneous disintegration of the nuclei of atoms of certain substances with the appearance of a stream of high-power charged particles. Substances capable of such a phenomenon are called radionuclides.

So what is radioactive radiation? Typically, this term refers to both radioactive and radiation emissions. At its core, it is a directed flow elementary particles significant power, causing ionization of any medium that gets in their path: air, liquids, metals, minerals and other substances, as well as biological tissues. Ionization of any material leads to a change in its structure and basic properties. Biological tissues, incl. the human body are subject to changes that are incompatible with their life activity.

Different types of radioactive radiation have different penetrating and ionizing powers. The damaging properties depend on the following main characteristics of radionuclides: type of radiation, flow power, half-life. Ionizing ability is assessed by a specific indicator: the number of ions of the ionized substance formed at a distance of 10 mm along the path of radiation penetration.

Negative effects on humans

Radiation exposure in humans leads to structural changes in the tissues of the body. As a result of ionization, free radicals appear in them, which are chemically active molecules that damage and kill cells. The gastrointestinal, genitourinary and hematopoietic systems are the first and most severely affected. Severe symptoms of their dysfunction appear: nausea and vomiting, fever, bowel dysfunction.

Radiation cataracts, caused by exposure to radiation to the eye tissue, are quite typical. There are other serious consequences radiation exposure: vascular sclerosis, sharp decrease in immunity, hematogenous problems. Damage to the genetic mechanism is especially dangerous. The resulting active radicals can change the structure of the main carrier genetic information— DNA. Such disorders can lead to unpredictable mutations that affect subsequent generations.

The degree of damage to the human body depends on what types of radioactive radiation occurred, the intensity and individual susceptibility of the body.

The main indicator is the radiation dose, which shows how much radiation has penetrated the body. It has been established that a single large dose is much more dangerous than the accumulation of such a dose during prolonged exposure to low-power radiation. The amount of radiation absorbed by the body is measured in everts (Ev). Any living environment

has a certain level of radiation. A background radiation level of no higher than 0.18-0.2 mEv/h or 20 microroentgens is considered normal. The critical level leading to death is estimated at 5.5-6.5 Ev.

Types of radiation

As noted, radioactive radiation and its types can affect the human body in different ways. The following main types of radiation can be distinguished.

1. Corpuscular-type radiation, which is a stream of particles:
2. Alpha radiation. This is a stream composed of alpha particles that have enormous ionizing ability, but the penetration depth is small. Even a piece of thick paper can stop such particles. A person's clothing plays the role of protection quite effectively.
3. Beta radiation is caused by a stream of beta particles traveling at speeds close to the speed of light. Due to the enormous speed, these particles have increased penetrating ability, but their ionizing capabilities are lower than in the previous version. Window windows or a metal sheet 8-10 mm thick can serve as a screen from this radiation. It is very dangerous for humans if it comes into direct contact with the skin.

Neutron radiation consists of neutrons and has the greatest damaging effect. Sufficient protection against them is provided by materials that contain hydrogen in their structure: water, paraffin, polyethylene, etc.

1. Wave radiation, which is the radial propagation of energy:
2. X-rays, or X-rays. These quantum rays are in many ways similar to gamma rays, but their penetrating capabilities are somewhat reduced. This type of wave is produced in vacuum X-ray units by striking electrons against a special target. The diagnostic purpose of this radiation is well known. However, it should be remembered that its prolonged effect can cause serious harm to the human body.

How can a person become irradiated?

A person receives radioactive radiation if radiation penetrates his body. It can happen in 2 ways: external and internal influence. In the first case, the source of radioactive radiation is located outside, and the person various reasons falls into the field of his activities without proper protection. Internal exposure occurs when a radionuclide penetrates into the body. This can happen when consuming irradiated foods or liquids, with dust and gases, when breathing contaminated air, etc.

External sources of radiation can be divided into 3 categories:

1. Natural sources: heavy chemical elements and radioactive isotopes.
2. Artificial sources: technical devices, providing radiation during the corresponding nuclear reactions.
3. Induced radiation: different environments after exposure to intense ionizing radiation, they themselves become a source of radiation.

The most dangerous objects in terms of possible radiation exposure include the following radiation sources:

1. Industries related to the extraction, processing, enrichment of radionuclides, production of nuclear fuel for reactors, in particular the uranium industry.
2. Nuclear reactors of any type, incl. in power plants and ships.
3. Radiochemical enterprises engaged in the regeneration of nuclear fuel.
4. Places for storing (disposal) waste of radioactive substances, as well as enterprises for their processing.
5. Using radiation emissions in different industries: medicine, geology, Agriculture, industry, etc.
6. Trial nuclear weapons, nuclear explosions for peaceful purposes.

Manifestation of damage to the body

The characteristics of radioactive radiation play a decisive role in the degree of damage to the human body. As a result of exposure, radiation sickness develops, which can have two directions: somatic and genetic damage. Based on the time of manifestation, early and late effects are distinguished.

Early effect reveals characteristic symptoms in the period from 1 hour to 2 months. The following signs are considered typical: skin redness and peeling, cloudiness of the eye lens, disruption of the hematopoietic process. The extreme option with a large dose of radiation is death. Local damage is characterized by such signs as radiation burn skin and mucous membrane.

Long-term manifestations are revealed after 3-5 months, or even after several years. In this case, persistent skin lesions, malignant tumors of various localizations, a sharp deterioration in immunity, changes in blood composition (a significant decrease in the level of red blood cells, leukocytes, platelets and neutrophils) are noted. As a result, various infectious diseases, life expectancy is significantly reduced.

To prevent human exposure to ionizing radiation, various types of protection are used, which depend on the type of radiation. In addition, strict standards are regulated on the maximum duration of a person’s stay in the radiation zone, the minimum distance to the radiation source, the use of personal protective equipment and the installation of protective screens.

Radioactive radiation can have a strong destructive effect on all tissues of the human body.

At the same time, it is also used in the treatment of various diseases. It all depends on the radiation dose received by a person in a single or long-term mode. Only strict adherence to radiation protection standards will help maintain health, even if you are within the range of a radiation source. Atomic energy is quite actively used for peaceful purposes, for example, in the operation of an X-ray machine, an accelerator installation, which made it possible to distribute ionizing radiation in national economy

. Considering that a person is exposed to it every day, it is necessary to find out what the consequences of dangerous contact can be and how to protect yourself.

Main characteristics Ionizing radiation is a type of radiant energy that enters a specific environment, causing the process of ionization in the body. Similar characteristic ionizing radiation suitable for x-rays

, radioactive and high energies, and much more.

Known varieties are radioactive irradiations, which appear due to arbitrary fission atomic nucleus, which causes a transformation of chemicals, physical properties. Substances that can decay are considered radioactive.

They can be artificial (seven hundred elements), natural (fifty elements) - thorium, uranium, radium. It should be noted that they have carcinogenic properties; toxins are released as a result of exposure to humans and can cause cancer and radiation sickness.

It should be noted the following types ionizing radiation that affects the human body:

Alpha

Considered to be positively charged helium ions, which appear in the event of nuclear decay heavy elements. Protection against ionizing radiation is carried out using a piece of paper or cloth.

Beta

– a flow of negatively charged electrons that appear in the event of the decay of radioactive elements: artificial, natural. Damage factor much higher than that of the previous species. As protection you will need a thick screen, more durable. Such radiations include positrons.

Gamma

– a hard electromagnetic oscillation that appears after the decay of nuclei of radioactive substances. A high penetrating factor is observed and is the most dangerous radiation of the three listed for the human body. To shield the rays, you need to use special devices. For this you will need good and durable materials: water, lead and concrete.

X-ray

Ionizing radiation is generated in the process of working with a tube and complex installations. The characteristic resembles gamma rays. The difference lies in the origin and wavelength. There is a penetrating factor.

Neutron

Neutron radiation is a stream of uncharged neutrons that are part of nuclei, except hydrogen. As a result of irradiation, substances receive a portion of radioactivity. There is the largest penetrating factor. All these types of ionizing radiation are very dangerous.

Main sources of radiation

Sources of ionizing radiation can be artificial or natural. Basically, the human body receives radiation from natural sources, these include:

• terrestrial radiation;
• internal irradiation.

As for the sources of terrestrial radiation, many of them are carcinogenic. These include:

• Uranus;
• potassium;
• thorium;
• polonium;
• lead;
• rubidium;
• radon.

The danger is that they are carcinogenic. Radon is a gas that has no odor, color, or taste. It is seven and a half times heavier than air. Its decay products are much more dangerous than gas, so the impact on the human body is extremely tragic.

Artificial sources include:

• nuclear energy;
• processing factories;
• uranium mines;
• burial grounds with radioactive waste;
• X-ray machines;
• nuclear explosion;
• scientific laboratories;
• radionuclides, which are actively used in modern medicine;
• lighting devices;
• computers and phones;
• Appliances.

If these sources are nearby, there is a factor of the absorbed dose of ionizing radiation, the unit of which depends on the duration of exposure to the human body.

The operation of sources of ionizing radiation occurs every day, for example: when you work at a computer, watch a TV show or talk on mobile phone, smartphone. All of these sources are to some extent carcinogenic and can cause severe and fatal diseases.

The placement of sources of ionizing radiation includes a list of important, responsible work related to the development of a project for the location of irradiation installations. All radiation sources contain a certain unit of radiation, each of which has a specific effect on the human body. This includes manipulations carried out for installation and commissioning of these installations.

It should be noted that disposal of sources of ionizing radiation is mandatory.

This is a process that helps decommission generation sources. This procedure consists of technical and administrative measures that are aimed at ensuring the safety of personnel and the population, and there is also a protection factor environment. Carcinogenic sources and equipment are a huge danger to the human body, so they must be disposed of.

Features of radiation registration

The characteristics of ionizing radiation show that they are invisible, odorless and colorless, so they are difficult to notice.

For this purpose, there are methods for recording ionizing radiation. As for the methods of detection and measurement, everything is done indirectly, using some property as a basis.

The following methods for detecting ionizing radiation are used:

• Physical: ionization, proportional counter, gas-discharge Geiger-Muller counter, ionization chamber, semiconductor counter.
• Calorimetric detection method: biological, clinical, photographic, hematological, cytogenetic.
• Luminescent: fluorescent and scintillation counters.
• Biophysical method: radiometry, calculation.

Dosimetry of ionizing radiation is carried out using instruments; they are able to determine the radiation dose. The device includes three main parts - a pulse counter, a sensor, and a power source. Radiation dosimetry is possible thanks to a dosimeter or radiometer.

Effects on humans

The effect of ionizing radiation on the human body is especially dangerous. The following consequences are possible:

• there is a factor of very profound biological change;
• there is a cumulative effect of a unit of absorbed radiation;
• the effect manifests itself over time, as there is a latent period;
• everyone has internal organs, systems have different sensitivity to a unit of absorbed radiation;
• radiation affects all offspring;
• the effect depends on the unit of radiation absorbed, the radiation dose, and duration.

Despite the use of radiation devices in medicine, their effects can be harmful. Biological action ionizing radiation in the process of uniform irradiation of the body, calculating 100% of the dose, the following occurs:

• bone marrow – unit of absorbed radiation 12%;
• lungs – at least 12%;
• bones – 3%;
• testes, ovaries– absorbed dose of ionizing radiation about 25%;
• thyroid gland– absorbed dose unit about 3%;
• mammary glands – approximately 15%;
• other tissues - the unit of absorbed radiation dose is 30%.

As a result, there may be various diseases up to oncology, paralysis and radiation sickness. It is extremely dangerous for children and pregnant women, as abnormal development of organs and tissues occurs. Toxins and radiation are sources of dangerous diseases.

The term "radiation" comes from the Latin word radius and means ray. In the broadest sense of the word, radiation covers all types of radiation existing in nature: radio waves, infrared radiation, visible light, ultraviolet and, finally, ionizing radiation. All these types of radiation, having an electromagnetic nature, differ in wavelength, frequency and energy.

There are also radiations that are of a different nature and are streams of various particles, for example, alpha particles, beta particles, neutrons, etc.

Every time a barrier appears in the path of radiation, it transfers some or all of its energy to this barrier. And the final effect of radiation depends on how much energy was transferred and absorbed in the body. Everyone knows the pleasure of a bronze tan and the grief of the hardest sunburn. It is obvious that overexposure to any type of radiation is fraught with unpleasant consequences.

Ionizing types of radiation are the most important for human health. As ionizing radiation passes through tissue, it transfers energy and ionizes atoms in molecules that play an important role biological role. Therefore, exposure to any type of ionizing radiation can affect health in one way or another. These include:

Alpha radiation these are heavy positively charged particles, consisting of two protons and two neutrons, tightly bound together. In nature, alpha particles arise from the decay of atoms of heavy elements such as uranium, radium and thorium. In the air, alpha radiation travels no more than five centimeters and, as a rule, is completely blocked by a sheet of paper or the outer dead layer of skin. However, if a substance that emits alpha particles enters the body through food or inhaled air, it irradiates internal organs and becomes potentially dangerous.

Beta radiation these are electrons that are much smaller than alpha particles and can penetrate several centimeters deep into the body. You can protect yourself from it with a thin sheet of metal, window glass, and even ordinary clothing. When beta radiation reaches unprotected areas of the body, it usually affects the upper layers of the skin. During the Chernobyl nuclear power plant accident in 1986, firefighters suffered skin burns as a result of very strong exposure to beta particles. If a substance that emits beta particles enters the body, it will irradiate internal tissues.

Gamma radiation these are photons, i.e. electromagnetic wave carrying energy. In the air it can travel long distances, gradually losing energy as a result of collisions with atoms of the medium. Intense gamma radiation, if not protected from it, can damage not only the skin, but also internal tissues. Dense and heavy materials such as iron and lead are excellent barriers to gamma radiation.

X-ray radiation similar to gamma radiation emitted by nuclei, but it is produced artificially in an X-ray tube, which itself is not radioactive. Since the X-ray tube is powered by electricity, the emission of X-rays can be turned on or off using a switch.

Neutron radiation is formed during the fission of the atomic nucleus and has high penetrating ability. Neutrons can be stopped by a thick concrete, water or paraffin barrier. Fortunately, in peaceful life, there is practically no neutron radiation anywhere except in the immediate vicinity of nuclear reactors.

In relation to X-ray and gamma radiation, the definitions often used are: "hard" And "soft". This is a relative characteristic of its energy and the associated penetrating power of radiation (“hard” greater energy and penetrating power, “soft” less). Ionizing radiation and its penetrating ability

The number of neutrons in a nucleus determines whether a given nucleus is radioactive. In order for the nucleus to be in a stable state, the number of neutrons, as a rule, must be slightly higher than the number of protons. In a stable nucleus, protons and neutrons are so tightly bound together by nuclear forces that not a single particle can escape. Such a core will always remain in a balanced and calm state. However, the situation is completely different if the number of neutrons upsets the equilibrium. In this case, the nucleus has excess energy and simply cannot be kept intact. Sooner or later it will release its excess energy.

Different nuclei release their energy different ways: in the form of electromagnetic waves or particle streams. This energy is called radiation. Radioactive decay

The process during which unstable atoms give off their excess energy is called radioactive decay, and such atoms themselves are called radionuclides. Light nuclei with a small number of protons and neutrons become stable after one decay. When heavy nuclei, such as uranium, decay, the resulting nucleus is still unstable and, in turn, decays further, forming a new nucleus, etc. The chain of nuclear transformations ends with the formation of a stable nucleus. Such chains can form radioactive families. The radioactive families of uranium and thorium are known in nature.

An idea of ​​the intensity of decay is given by the concept of half-life - the period during which half of the unstable nuclei of a radioactive substance will decay. The half-life of each radionuclide is unique and unchanged. One radionuclide, for example, krypton-94, is born in nuclear reactor and disintegrates very quickly. Its half-life is less than a second. Another, for example, potassium-40, was formed at the birth of the Universe and is still preserved on the planet. Its half-life is measured in billions of years.

Today we’ll talk about what radiation is in physics. Let's talk about the nature of electronic transitions and give an electromagnetic scale.

Deity and atom

The structure of matter became a subject of interest to scientists more than two thousand years ago. Ancient Greek philosophers asked questions about how air differs from fire, and earth from water, why marble is white and coal is black. They created complex systems of interdependent components, refuted or supported each other. And the most incomprehensible phenomena, for example, a lightning strike or sunrise, were attributed to the action of the gods.

Once, after observing the steps of the temple for many years, one scientist noticed: each foot that stands on a stone carries away a tiny particle of matter. Over time, the marble changed shape and sagged in the middle. The name of this scientist is Leucippus, and he called tiny particles atoms, indivisible. This began the path to studying what radiation is in physics.

Easter and light

Then dark times came and science was abandoned. Everyone who tried to study the forces of nature was dubbed witches and sorcerers. But, oddly enough, it was religion that gave impetus to the further development of science. The study of what radiation is in physics began with astronomy.

The time for celebrating Easter was calculated differently each time in those days. A complex system relationship between the day spring equinox, the 26-day lunar cycle and 7-day week did not allow us to compile date tables for the celebration of Easter for more than a couple of years. But the church had to plan everything in advance. Therefore, Pope Leo X ordered the compilation of more accurate tables. This required careful observation of the movements of the Moon, stars and Sun. And in the end, Nicolaus Copernicus realized: the Earth is not flat and not the center of the universe. A planet is a ball that revolves around the Sun. And the Moon is a sphere in Earth's orbit. Of course, one might ask, “What does all this have to do with what radiation is in physics?” Let's reveal it now.

Oval and beam

Later, Kepler supplemented the Copernican system by establishing that the planets move in oval orbits, and this movement is uneven. But it was precisely that first step that instilled in humanity an interest in astronomy. And there it was not far from the questions: “What is a star?”, “Why do people see its rays?” and “How does one luminary differ from another?” But first you will have to move from huge objects to the smallest. And then we come to radiation, a concept in physics.

Atom and raisin

At the end of the nineteenth century, sufficient knowledge had accumulated about the smallest chemical units of matter - atoms. They were known to be electrically neutral, but to contain both positively and negatively charged elements.

Many assumptions have been made: that positive charges are distributed in a negative field, like raisins in a bun, and that an atom is a drop of dissimilarly charged liquid parts. But Rutherford's experience clarified everything. He proved that at the center of the atom there is a positive heavy nucleus, and around it there are light negative electrons. And the configuration of the shells is different for each atom. This is where the peculiarities of radiation in the physics of electronic transitions lie.

Boron and orbit

When scientists found out that the light negative parts of the atom are electrons, another question arose - why they do not fall onto the nucleus. After all, according to Maxwell’s theory, any moving charge radiates, and therefore loses energy. But atoms existed as long as the universe, and were not going to annihilate. Bohr came to the rescue. He postulated that electrons are in certain stationary orbits around the atomic nucleus, and can only be in them. The transition of an electron between orbits is carried out by a jerk with the absorption or emission of energy. This energy could be, for example, a quantum of light. In essence, we have now outlined the definition of radiation in particle physics.

Hydrogen and photography

Initially, photography technology was invented as a commercial project. People wanted to remain for centuries, but not everyone could afford to order a portrait from an artist. And photographs were cheap and did not require such a large investment. Then the art of glass and silver nitrate put military affairs into its service. And then science began to take advantage of photosensitive materials.

Spectra were photographed first. It has long been known that hot hydrogen emits specific lines. The distance between them obeyed a certain law. But the spectrum of helium was more complex: it contained the same set of lines as hydrogen, and one more. The second series no longer obeyed the law derived for the first series. Here Bohr's theory came to the rescue.

It turned out that there is only one electron in a hydrogen atom, and it can move from all higher excited orbits to one lower one. This was the first series of lines. Heavier atoms are more complex.

Lens, grating, spectrum

This marked the beginning of the use of radiation in physics. Spectral analysis is one of the most powerful and reliable ways to determine the composition, quantity and structure of a substance.

1. The electron emission spectrum will tell you what is contained in the object and what the percentage of a particular component is. This method is used in absolutely all areas of science: from biology and medicine to quantum physics.
2. The absorption spectrum will tell you which ions and in which positions are present in the lattice of the solid.
3. The rotational spectrum will demonstrate how far apart the molecules are inside the atom, how many and what kind of bonds each element has.

And the ranges of application of electromagnetic radiation are countless:

• radio waves explore the structure of very distant objects and the interior of planets;
• thermal radiation will tell about the energy of processes;
• visible light will tell you in which directions the brightest stars lie;
• ultraviolet rays will make it clear that high-energy interactions are occurring;
• The X-ray spectrum itself allows people to study the structure of matter (including the human body), and the presence of these rays in cosmic objects will notify scientists that there is a neutron star, a supernova explosion or a black hole at the focus of the telescope.

Pure black body

But there is a special section that studies what thermal radiation is in physics. Unlike atomic light, thermal emission of light has a continuous spectrum. And the best model object for calculations is an absolutely black body. This is an object that “catches” all the light falling on it, but does not release it back. Oddly enough, a black body emits radiation, and the maximum wavelength will depend on the temperature of the model. In classical physics, thermal radiation gave rise to a paradox. It turned out that any heated thing should radiate more and more energy until ultraviolet range its energy would not destroy the universe.

Max Planck was able to resolve the paradox. He introduced a new quantity, quantum, into the radiation formula. Without giving it anything special physical meaning, he opened up a whole world. Now quantization of quantities is the basis modern science. Scientists realized that fields and phenomena consist of indivisible elements, quanta. This led to deeper studies of matter. For example, modern world belongs to semiconductors. Previously, everything was simple: metal conducts current, other substances are dielectrics. And substances such as silicon and germanium (semiconductors) behave incomprehensibly in relation to electricity. To learn how to control their properties, it was necessary to create a whole theory and calculate everything p-n capabilities transitions.