Searching for a grating for X-ray radiation However, working with diffraction gratings encountered its own difficulties. The fact is that it is impossible to select the same type of grating for all radiation. For various radiations needed various gratings. Width of light grid lines

A lattice for X-rays was also found. But it was found. diffraction grating and for X-rays. Nature itself came to the rescue here. late XIX and the beginning of the 20th century, physicists intensively studied the structure of solids. It is known that many solids are

Series of X-rays External conditions do not have such a great influence on the X-ray spectra of atoms. Even when atoms come into contact chemical compounds, their internal layers are not rearranged. Therefore, the X-ray spectra of molecules are the same as the spectra

The task of converting long-wave radiation into visible light Natural light converters - luminescent substances - convert light with a wavelength shorter than that of visible light into visible light. However practical needs put forward a task

Experimental discovery of electromagnetic waves Parallel to theoretical studies Maxwell's equations were carried out experimental studies on the generation of electrical oscillations obtained when a conventional capacitor is discharged into electrical circuit, And

Chapter XI Problems of protection against radioactive radiation Problems of protection against radioactive radiation arise at various stages of the use of atomic energy: - at the lowest stage, which includes, for example, the mining of uranium, which is the main type of nuclear

I. Protection against radioactive radiation at nuclear plants 1) Doses of radioactive radiation are most often expressed in roentgens. Various international commissions found that for workers at nuclear plants the permissible weekly radiation dose is 0.3 roentgens. This dose

9.3. Turin scale When enough is enough large object has just been discovered, it is not known in advance what danger it may pose to the Earth in the near or more distant future. It is possible, although unlikely, that receiving as much as possible more observations in

9.4. Palermo technical scale for assessing the threat of collision of the Earth with asteroids and comets The Turin scale, discussed in the previous section, was developed primarily to describe and disseminate information about the asteroid-comet hazard by means of

SCALE OF ELECTROMAGNETIC RADIATIONS

We know that the length of electromagnetic waves can be very different: from values ​​​​of the order of 103 m (radio waves) to 10-8 cm (x-rays). Light is an insignificant part wide range electromagnetic waves. Nevertheless, it was during the study of this small part of the spectrum that other radiations with unusual properties were discovered.

Fundamental difference there is no difference between individual emissions. All of them are electromagnetic waves generated by accelerated moving charged particles. Electromagnetic waves are ultimately detected by their effect on charged particles. In a vacuum, radiation of any wavelength travels at a speed of 300,000 km/s. The boundaries between individual regions of the radiation scale are very arbitrary.

Radiations of different wavelengths differ from each other in the method of their receipt (antenna radiation, thermal radiation, radiation during deceleration of fast electrons, etc.) and registration methods.

All listed types electromagnetic radiation are also generated by space objects and are successfully studied using rockets, artificial satellites Earth and spaceships. This primarily applies to X-ray and gamma radiation, which are strongly absorbed by the atmosphere.

As the wavelength decreases quantitative differences in wavelengths lead to significant qualitative differences.

Radiations of different wavelengths differ greatly from each other in their absorption by matter. Short-wave radiation (X-rays and especially g-rays) are weakly absorbed. Substances that are opaque to optical waves are transparent to these radiations. The reflection coefficient of electromagnetic waves also depends on the wavelength. But the main difference between long-wave and short-wave radiation is that short-wave radiation reveals the properties of particles.

Radio waves

n= 105-1011 Hz, l»10-3-103 m.

Obtained using oscillatory circuits and macroscopic vibrators.

Properties: Radio waves of different frequencies and with different wavelengths are absorbed and reflected differently by media, and exhibit diffraction and interference properties.

Application: Radio communications, television, radar.

Infrared radiation (thermal)

n=3*1011-4*1014 Hz, l=8*10-7-2*10-3 m.

Emitted by atoms and molecules of matter. Infrared radiation is emitted by all bodies at any temperature. A person emits electromagnetic waves l»9*10-6 m.

Properties:

1. Passes through some opaque bodies, also through rain, haze, snow.

2. Produces a chemical effect on photographic plates.

3. Absorbed by a substance, it heats it.

4. Causes an internal photoelectric effect in germanium.

5. Invisible.

6. Capable of interference and diffraction phenomena.

Recorded by thermal, photoelectric and photographic methods.

Application: Obtain images of objects in the dark, night vision devices (night binoculars), and fog. Used in forensics, physiotherapy, and in industry for drying painted products, building walls, wood, and fruit.

Visible radiation

The part of electromagnetic radiation perceived by the eye (from red to violet):

n=4*1014-8*1014 Hz, l=8*10-7-4*10-7 m.

Properties: Reflects, refracts, affects the eye, is capable of the phenomena of dispersion, interference, diffraction.

Ultraviolet radiation

n=8*1014-3*1015 Hz, l=10-8-4*10-7 m (less than violet light).

Sources: gas-discharge lamps with quartz tubes (quartz lamps).

Radiated by everyone solids, for which t>1000оС, as well as luminous mercury vapor.

Properties: High chemical activity(decomposition of silver chloride, glow of zinc sulfide crystals), invisible, high penetrating power, kills microorganisms, in small doses has a beneficial effect on the human body (tanning), but in large doses has a negative effect biological effect: changes in cell development and metabolism, effects on the eyes.

Application: In medicine, in industry.

X-rays

Emitted during high acceleration of electrons, for example their deceleration in metals. Obtained using an X-ray tube: electrons in a vacuum tube (p = 10-3-10-5 Pa) are accelerated by an electric field at high voltage, reaching the anode, and are sharply decelerated upon impact. When braking, electrons move with acceleration and emit electromagnetic waves with a short length (from 100 to 0.01 nm).

Properties: Interference, X-ray diffraction on a crystal lattice, high penetrating power. Irradiation in large doses causes radiation sickness.

Application: In medicine (diagnosis of diseases internal organs), in industry (control of the internal structure of various products, welds).

g -Radiation

n=3*1020 Hz and more, l=3.3*10-11 m.

Sources: atomic nucleus ( nuclear reactions).

Properties: Has enormous penetrating power and has a strong biological effect.

Application: In medicine, manufacturing (g-flaw detection).

Conclusion

The entire scale of electromagnetic waves is evidence that all radiation has both quantum and wave properties. Quantum and wave properties in this case they do not exclude, but complement each other. Wave properties appear more clearly at low frequencies and less clearly at high frequencies. And vice versa, quantum properties appear more clearly at high frequencies and less clearly at low frequencies. The shorter the wavelength, the brighter the quantum properties appear, and the longer the wavelength, the brighter the wave properties appear. All this serves as confirmation of the law of dialectics (transition quantitative changes in quality).

Technological progress has reverse side. Global use various equipment, powered by electricity, caused pollution, which was given the name - electromagnetic noise. In this article we will look at the nature of this phenomenon, the degree of its impact on the human body and protective measures.

What is it and sources of radiation

Electromagnetic radiation is electromagnetic waves that arise when a magnetic or electric field. Modern physics interprets this process within the framework of the theory of wave-particle duality. That is, the minimum portion of electromagnetic radiation is a quantum, but at the same time it has frequency-wave properties that determine its main characteristics.

Radiation frequency spectrum electromagnetic field, allows us to classify it into the following types:

• radio frequency (these include radio waves);
• thermal (infrared);
• optical (that is, visible to the eye);
• radiation in the ultraviolet spectrum and hard (ionized).

A detailed illustration of the spectral range (electromagnetic radiation scale) can be seen in the figure below.

Nature of radiation sources

Depending on their origin, sources of radiation of electromagnetic waves in world practice are usually classified into two types, namely:

• disturbances of the electromagnetic field of artificial origin;
• radiation coming from natural sources.

Radiations emanating from the magnetic field around the Earth, electrical processes in the atmosphere of our planet, nuclear fusion in the depths of the sun - they are all of natural origin.

Concerning artificial sources, then they side effect, caused by the work of various electrical mechanisms and instruments.

The radiation emanating from them can be low-level and high-level. The degree of intensity of the electromagnetic field radiation completely depends on the power levels of the sources.

Examples of sources with high levels of EMR include:

• Power lines are usually high-voltage;
• all types of electric transport, as well as the accompanying infrastructure;
• television and radio towers, as well as mobile and mobile communication stations;
• installations for converting the voltage of the electrical network (in particular, waves emanating from a transformer or distribution substation);
• elevators and other types of lifting equipment that use an electromechanical power plant.

Typical sources emitting low-level radiation include the following electrical equipment:

• almost all devices with a CRT display (for example: payment terminal or computer);
• various types of household appliances, from irons to climate control systems;
• engineering systems that provide electricity supply to various objects(this includes not only the power cable, but also related equipment, such as sockets and electricity meters).

Separately, it is worth highlighting special equipment used in medicine, which emits hard radiation(X-ray machines, MRI, etc.).

Impact on humans

In the course of numerous studies, radiobiologists have come to a disappointing conclusion - long-term radiation of electromagnetic waves can cause an “explosion” of diseases, that is, it causes the rapid development of pathological processes in the human body. Moreover, many of them cause disturbances at the genetic level.

Video: How electromagnetic radiation affects people.
https://www.youtube.com/watch?v=FYWgXyHW93Q

This occurs due to the fact that the electromagnetic field high level biological activity, which negatively affects living organisms. The influence factor depends on the following components:

• the nature of the radiation produced;
• how long and with what intensity it continues.

The effect on human health of radiation, which is of an electromagnetic nature, directly depends on the location. It can be either local or general. IN the latter case large-scale exposure occurs, such as radiation produced by power lines.

Accordingly, local irradiation refers to exposure to certain areas of the body. Coming from an electronic watch or mobile phone electromagnetic waves, shining example local impact.

Separately, it is necessary to note the thermal effect of high-frequency electromagnetic radiation on living matter. The field energy is converted into thermal energy(due to vibration of molecules), this effect is the basis for the operation of industrial microwave emitters used for heating various substances. In contrast to the benefits production processes, thermal effects on the human body can be harmful. From a radiobiological point of view, being near “warm” electrical equipment is not recommended.

It is necessary to take into account that in everyday life we ​​are regularly exposed to radiation, and this happens not only at work, but also at home or when moving around the city. Over time, the biological effect accumulates and intensifies. As electromagnetic noise increases, the number of characteristic brain diseases or nervous system. Note that radiobiology is a fairly young science, so the harm caused to living organisms from electromagnetic radiation has not been thoroughly studied.

The figure shows the level of electromagnetic waves produced by conventional household appliances.

Note that the field strength level decreases significantly with distance. That is, to reduce its effect, it is enough to move away from the source at a certain distance.

The formula for calculating the norm (standardization) of electromagnetic field radiation is specified in the relevant GOSTs and SanPiNs.

Radiation protection

In production, absorbing (protective) screens are actively used as means of protecting against radiation. Unfortunately, it is not possible to protect yourself from electromagnetic field radiation using such equipment at home, since it is not designed for this.

• in order to reduce the impact of electromagnetic field radiation to almost zero, you should move away from power lines, radio and television towers at a distance of at least 25 meters (the power of the source must be taken into account);
• for CRT monitors and TVs this distance is much smaller - about 30 cm;
• Electronic watches should not be placed close to the pillow; the optimal distance for them is more than 5 cm;
• as for radio and cell phones, bringing them closer than 2.5 centimeters is not recommended.

Note that many people know how dangerous it is to stand next to high voltage lines power transmission, but most people do not attach importance to ordinary household electrical appliances. Although it is enough to put system unit on the floor or move it further away, and you will protect yourself and your loved ones. We advise you to do this, and then measure the background from the computer using an electromagnetic field radiation detector to clearly verify its reduction.

This advice also applies to the placement of the refrigerator; many people place it near the kitchen table, which is practical, but unsafe.

No table can indicate the exact safe distance from specific electrical equipment, since radiation may vary, both depending on the device model and the country of manufacture. IN currently there is no single international standard, therefore in different countries standards may differ significantly.

The radiation intensity can be accurately determined using special device– fluxmeter. According to the standards adopted in Russia, the maximum permissible dose should not exceed 0.2 µT. We recommend taking measurements in the apartment using the above-mentioned device for measuring the degree of electromagnetic field radiation.

Try to reduce the time you are exposed to radiation, that is, do not stay near operating electrical devices for a long time. For example, it is not at all necessary to constantly stand at the electric stove or microwave oven while cooking. Regarding electrical equipment, you can notice that warm does not always mean safe.

Always turn off electrical appliances when not in use. People often leave various devices turned on, not taking into account that at this time electromagnetic radiation is emanating from electrical equipment. Turn off your laptop, printer or other equipment if not necessary once again be exposed to radiation, remember your safety.

Lesson objectives:

Lesson type:

Form: lecture with presentation

Karaseva Irina Dmitrievna, 17.12.2017

2492 287

Development content

Lesson summary on the topic:

Types of radiation. Electromagnetic wave scale

Lesson developed

teacher of the LPR State Institution “LOUSOSH No. 18”

Karaseva I.D.

Lesson objectives: consider the scale of electromagnetic waves, characterize waves of different frequency ranges; show the role of various types of radiation in human life, the influence of various types of radiation on humans; systematize material on the topic and deepen students’ knowledge about electromagnetic waves; develop oral speech students, creative skills of students, logic, memory; cognitive abilities; to develop students’ interest in studying physics; cultivate accuracy and hard work.

Lesson type: lesson in the formation of new knowledge.

Form: lecture with presentation

Equipment: computer, multimedia projector, presentation “Types of radiation.

Electromagnetic wave scale"

During the classes

Organizing time.

Motivation for educational and cognitive activities.

The Universe is an ocean of electromagnetic radiation. People live in it, for the most part, without noticing the waves permeating the surrounding space. While warming up by the fireplace or lighting a candle, a person makes the source of these waves work, without thinking about their properties. But knowledge is power: having discovered the nature of electromagnetic radiation, humanity during the 20th century has mastered and put into its service its most diverse types.

Setting the topic and goals of the lesson.

Today we will take a journey along the scale of electromagnetic waves, consider the types of electromagnetic radiation in different frequency ranges. Write down the topic of the lesson: “Types of radiation. Electromagnetic wave scale" (Slide 1)

We will study each radiation according to the following generalized plan (Slide 2).Generalized plan for studying radiation:

1. Range name

2. Wavelength

3. Frequency

4. Who was it discovered by?

5. Source

6. Receiver (indicator)

7. Application

8. Effect on humans

As you study the topic, you must complete the following table:

Table "Electromagnetic radiation scale"

Presentation of new material.

(Slide 3)

The length of electromagnetic waves can be very different: from values ​​of the order of 10 13 m (low frequency vibrations) up to 10 -10 m ( -rays). Light makes up a tiny part of the broad spectrum of electromagnetic waves. However, it was during the study of this small part of the spectrum that other radiations with unusual properties were discovered.
It is customary to highlight low frequency radiation, radio radiation, infrared rays, visible light, ultraviolet rays, x-rays and -radiation. The shortest wavelength -radiation emits atomic nuclei.

There is no fundamental difference between individual radiations. All of them are electromagnetic waves generated by charged particles. Electromagnetic waves are ultimately detected by their effect on charged particles . In a vacuum, radiation of any wavelength travels at a speed of 300,000 km/s. The boundaries between individual regions of the radiation scale are very arbitrary.

(Slide 4)

Radiation of different wavelengths differ from each other in the way they are receiving(antenna radiation, thermal radiation, radiation during braking of fast electrons, etc.) and registration methods.

All of the listed types of electromagnetic radiation are also generated by space objects and are successfully studied using rockets, artificial Earth satellites and spacecraft. First of all, this applies to X-ray and - radiation strongly absorbed by the atmosphere.

Quantitative differences in wavelengths lead to significant qualitative differences.

Radiations of different wavelengths differ greatly from each other in their absorption by matter. Short-wave radiation (X-ray and especially -rays) are weakly absorbed. Substances that are opaque to optical waves are transparent to these radiations. The reflection coefficient of electromagnetic waves also depends on the wavelength. But the main difference between long-wave and short-wave radiation is that short-wave radiation reveals the properties of particles.

Let's consider each radiation.

(Slide 5)

Low frequency radiation occurs in the frequency range from 3 10 -3 to 3 10 5 Hz. This radiation corresponds to a wavelength of 10 13 - 10 5 m. Radiation of such relatively low frequencies can be neglected. The source of low-frequency radiation is alternating current generators. Used in melting and hardening of metals.

(Slide 6)

Radio waves occupy the frequency range 3·10 5 - 3·10 11 Hz. They correspond to a wavelength of 10 5 - 10 -3 m. Source radio waves, as well as Low frequency radiation is alternating current. Also the source is a radio frequency generator, stars, including the Sun, galaxies and metagalaxies. The indicators are a Hertz vibrator and an oscillatory circuit.

High frequency radio waves, compared to low-frequency radiation leads to noticeable emission of radio waves into space. This allows them to be used to transmit information over various distances. Speech, music (broadcasting), telegraph signals (radio communications), images are transmitted various objects(radar).

Radio waves are used to study the structure of matter and the properties of the medium in which they propagate. Radio emission research space objects- subject of radio astronomy. In radiometeorology, processes are studied based on the characteristics of received waves.

(Slide 7)

Infrared radiation occupies the frequency range 3 10 11 - 3.85 10 14 Hz. They correspond to a wavelength of 2·10 -3 - 7.6·10 -7 m.

Infrared radiation was discovered in 1800 by astronomer William Herschel. Studying the rise in temperature of a thermometer being heated visible light, Herschel discovered the greatest heating of the thermometer outside the region of visible light (beyond the red region). Not visible radiation, given its place in the spectrum, was called infrared. The source of infrared radiation is the radiation of molecules and atoms under thermal and electrical influences. A powerful source of infrared radiation is the Sun; about 50% of its radiation lies in the infrared region. On infrared radiation accounts for a significant share (from 70 to 80%) of the radiation energy of incandescent lamps with tungsten filament. Infrared radiation emits electric arc and various gas discharge lamps. The radiation of some lasers lies in the infrared region of the spectrum. Indicators of infrared radiation are photos and thermistors, special photo emulsions. Infrared radiation is used to dry wood, food products and various paint and varnish coatings (infrared heating), for signaling in poor visibility, makes it possible to use optical devices that allow you to see in the dark, as well as with remote control. Infrared rays used to aim shells and missiles at targets and to detect a camouflaged enemy. These rays make it possible to determine the difference in temperatures of individual areas of the surface of the planets, the structural features of the molecules of matter ( spectral analysis). Infrared photography is used in biology when studying plant diseases, in medicine when diagnosing skin and vascular diseases, and in forensics when detecting counterfeits. Causes fever when exposed to humans human body.

(Slide 8)

Visible radiation - the only range of electromagnetic waves perceived by the human eye. Light waves occupy a fairly narrow range: 380 - 670 nm ( = 3.85 10 14 - 8 10 14 Hz). The source of visible radiation is valence electrons in atoms and molecules, changing their position in space, as well as free charges, moving quickly. This part of the spectrum gives a person maximum information about the world around us. In terms of its physical properties, it is similar to other spectral ranges, being only a small part of the spectrum of electromagnetic waves. Radiation having different lengths waves (frequencies) in the range of visible radiation, has different physiological effects onto the retina of the human eye, causing the psychological sensation of light. Color is not a property of an electromagnetic light wave in itself, but a manifestation of an electrochemical action physiological system human: eyes, nerves, brain. Approximately, we can name seven primary colors distinguished by the human eye in the visible range (in order of increasing frequency of radiation): red, orange, yellow, green, blue, indigo, violet. Memorizing the sequence of the primary colors of the spectrum is facilitated by a phrase, each word of which begins with the first letter of the name of the primary color: “Every Hunter Wants to Know Where the Pheasant Sits.” Visible radiation can influence the flow chemical reactions in plants (photosynthesis) and in animals and humans. Visible radiation is emitted by certain insects (fireflies) and some deep-sea fish due to chemical reactions in the body. Plant uptake carbon dioxide As a result of the process of photosynthesis and oxygen release, it helps maintain biological life on the ground. Visible radiation is also used when illuminating various objects.

Light is the source of life on Earth and at the same time the source of our ideas about the world around us.

(Slide 9)

Ultraviolet radiation, electromagnetic radiation invisible to the eye, occupying the spectral region between visible and x-ray radiation within wavelengths of 3.8 ∙ 10 -7 - 3 ∙ 10 -9 m ( = 8 * 10 14 - 3 * 10 16 Hz). Ultraviolet radiation was discovered in 1801 by the German scientist Johann Ritter. By studying the blackening of silver chloride under the influence of visible light, Ritter discovered that silver blackens even more effectively in the region beyond the violet end of the spectrum, where visible radiation is absent. The invisible radiation that caused this blackening was called ultraviolet radiation.

The source of ultraviolet radiation is the valence electrons of atoms and molecules, as well as rapidly moving free charges.

Radiation from solids heated to temperatures of -3000 K contains a noticeable proportion of ultraviolet radiation of a continuous spectrum, the intensity of which increases with increasing temperature. More powerful source ultraviolet radiation - any high-temperature plasma. For various applications ultraviolet radiation, mercury, xenon and other gas-discharge lamps are used. Natural sources of ultraviolet radiation - the Sun, stars, nebulae and others space objects. However, only the long-wave part of their radiation (  290 nm) reaches earth's surface. To register ultraviolet radiation at

 = 230 nm, conventional photographic materials are used; in the shorter wavelength region, special low-gelatin photographic layers are sensitive to it. Photoelectric receivers are used that use the ability of ultraviolet radiation to cause ionization and the photoelectric effect: photodiodes, ionization chambers, photon counters, photomultipliers.

In small doses, ultraviolet radiation has a beneficial, healing effect on humans, activating the synthesis of vitamin D in the body, as well as causing tanning. A large dose of ultraviolet radiation can cause skin burns and cancer (80% curable). In addition, excessive ultraviolet radiation weakens immune system body, contributing to the development of certain diseases. Ultraviolet radiation also has a bactericidal effect: under the influence of this radiation, pathogenic bacteria die.

Ultraviolet radiation is used in fluorescent lamps, in forensic science (using photographs to detect forgeries of documents), in art history (using ultraviolet rays traces of restoration invisible to the eye can be found in the paintings). Window glass practically does not transmit ultraviolet radiation, because It is absorbed by iron oxide, which is part of the glass. For this reason, even on a hot sunny day you cannot sunbathe in a room with the window closed.

The human eye does not see ultraviolet radiation because... The cornea of ​​the eye and the eye lens absorb ultraviolet radiation. Ultraviolet radiation is visible to some animals. For example, a pigeon navigates by the Sun even in cloudy weather.

(Slide 10)

X-ray radiation - it's electromagnetic ionizing radiation, occupying the spectral region between gamma and ultraviolet radiation within wavelengths from 10 -12 - 1 0 -8 m (frequencies 3 * 10 16 - 3-10 20 Hz). X-rays were discovered in 1895 German physicist V.K. X-ray. The most common source of X-ray radiation is an X-ray tube, in which electrons accelerated by an electrical field bombard a metal anode. X-ray radiation can be produced by bombarding a target with ions high energy. Some can also serve as sources of X-ray radiation. radioactive isotopes, synchrotrons are electron storage devices. Natural sources X-ray radiation is the Sun and other space objects

Images of objects in X-ray radiation are obtained on special X-ray photographic film. X-ray radiation can be recorded using an ionization chamber, scintillation counter, secondary electron or channel electron multipliers, microchannel plates. Thanks to its high penetrating ability x-ray radiation used in X-ray diffraction analysis (research of the structure crystal lattice), when studying the structure of molecules, detecting defects in samples, in medicine (X-rays, fluorography, treatment cancer diseases), in flaw detection (detection of defects in castings, rails), in art history (detection of ancient paintings hidden under a layer of late painting), in astronomy (when studying X-ray sources), and forensics. A large dose of X-ray radiation leads to burns and changes in the structure of human blood. Creation of X-ray receivers and placement of them on space stations made it possible to detect X-ray emission from hundreds of stars, as well as shells supernovas and entire galaxies.

(Slide 11)

Gamma radiation - short-wave electromagnetic radiation, occupying the entire frequency range  = 8∙10 14 - 10 17 Hz, which corresponds to wavelengths  = 3.8·10 -7 - 3∙10 -9 m. Gamma radiation was discovered by the French scientist Paul Villard in 1900.

While studying the radiation of radium in a strong magnetic field, Villar discovered short-wave electromagnetic radiation that does not deflect, like light, magnetic field. It was called gamma radiation. Gamma radiation is associated with nuclear processes, radioactive decay phenomena that occur with certain substances, both on Earth and in space. Gamma radiation can be detected using ionization and bubble chambers, as well as using special photographic emulsions. Used in research nuclear processes, in flaw detection. Gamma radiation has a negative effect on humans.

(Slide 12)

So, low frequency radiation, radio waves, infrared radiation, visible radiation, ultraviolet radiation, x-rays,-radiation are various types of electromagnetic radiation.

If you mentally arrange these types according to increasing frequency or decreasing wavelength, you will get a wide continuous spectrum - a scale of electromagnetic radiation (teacher shows scale). Dangerous types of radiation include: gamma radiation, x-rays and ultraviolet radiation, the rest are safe.

The division of electromagnetic radiation into ranges is conditional. There is no clear boundary between the regions. The names of the regions have developed historically; they only serve as a convenient means of classifying radiation sources.

(Slide 13)

All ranges of the electromagnetic radiation scale have general properties:

physical nature all radiation is the same

all radiation propagates in vacuum at the same speed, equal to 3 * 10 8 m/s

all radiations exhibit common wave properties (reflection, refraction, interference, diffraction, polarization)

5. Summing up the lesson

At the end of the lesson, students finish working on the table.

(Slide 14)

Conclusion:

The entire scale of electromagnetic waves is evidence that all radiation has both quantum and wave properties.

Quantum and wave properties in this case do not exclude, but complement each other.

Wave properties appear more clearly at low frequencies and less clearly at high frequencies. Conversely, quantum properties appear more clearly at high frequencies and less clearly at low frequencies.

The shorter the wavelength, the brighter the quantum properties appear, and the longer the wavelength, the brighter the wave properties appear.

All this serves as confirmation of the law of dialectics (the transition of quantitative changes into qualitative ones).

Abstract (learn), fill in the table

last column (effect of EMR on humans) and

prepare a report on the use of EMR

Development content

GU LPR "LOUSOSH No. 18"

Lugansk

Karaseva I.D.

GENERALIZED RADIATION STUDY PLAN

1. Range name.

2. Wavelength

3. Frequency

4. Who was it discovered by?

5. Source

6. Receiver (indicator)

7. Application

8. Effect on humans

TABLE “ELECTROMAGNETIC WAVE SCALE”

Name of radiation

Wavelength

Frequency

Opened by

Source

Receiver

Application

Effect on humans

The radiations differ from each other:

• by method of receipt;
• by registration method.

Quantitative differences in wavelengths lead to significant qualitative differences; they are absorbed differently by matter (short-wave radiation - X-rays and gamma radiation) - are weakly absorbed.

Short-wave radiation reveals the properties of particles.

Low frequency vibrations

Wavelength (m)

10 13 - 10 5

Frequency Hz)

3 · 10 -3 - 3 · 10 5

Source

Rheostatic alternator, dynamo,

Hertz vibrator,

Generators in electrical networks (50 Hz)

Machine generators of high (industrial) frequency (200 Hz)

Telephone networks (5000Hz)

Sound generators (microphones, loudspeakers)

Receiver

Electrical devices and motors

History of discovery

Oliver Lodge (1893), Nikola Tesla (1983)

Application

Cinema, radio broadcasting (microphones, loudspeakers)

Radio waves

Wavelength(m)

Frequency Hz)

10 5 - 10 -3

Source

3 · 10 5 - 3 · 10 11

Oscillatory circuit

Macroscopic vibrators

Stars, galaxies, metagalaxies

Receiver

History of discovery

Sparks in the gap of the receiving vibrator (Hertz vibrator)

Glow of a gas discharge tube, coherer

B. Feddersen (1862), G. Hertz (1887), A.S. Popov, A.N. Lebedev

Application

Extra long- Radio navigation, radiotelegraph communication, transmission of weather reports

Long– Radiotelegraph and radiotelephone communications, radio broadcasting, radio navigation

Average- Radiotelegraphy and radiotelephone communications, radio broadcasting, radio navigation

Short- amateur radio communications

VHF- space radio communications

DMV- television, radar, radio relay communications, cellular telephone communications

SMV- radar, radio relay communications, celestial navigation, satellite television

MMV- radar

Infrared radiation

Wavelength(m)

2 · 10 -3 - 7,6∙10 -7

Frequency Hz)

3∙10 11 - 3,85∙10 14

Source

Any heated body: candle, stove, radiator, electric lamp incandescent

A person emits electromagnetic waves with a length of 9 · 10 -6 m

Receiver

Thermoelements, bolometers, photocells, photoresistors, photographic films

History of discovery

W. Herschel (1800), G. Rubens and E. Nichols (1896),

Application

In forensic science, photographing earthly objects in fog and darkness, binoculars and sights for shooting in the dark, heating the tissues of a living organism (in medicine), drying wood and painted car bodies, alarm systems for protecting premises, infrared telescope.

Visible radiation

Wavelength(m)

6,7∙10 -7 - 3,8 ∙10 -7

Frequency Hz)

4∙10 14 - 8 ∙10 14

Source

Sun, incandescent lamp, fire

Receiver

Eye, photographic plate, photocells, thermocouples

History of discovery

M. Melloni

Application

Vision

Biological life

Ultraviolet radiation

Wavelength(m)

3,8 ∙10 -7 - 3∙10 -9

Frequency Hz)

8 ∙ 10 14 - 3 · 10 16

Source

Contains sunlight

Gas discharge lamps with quartz tube

Emitted by all solids with a temperature greater than 1000 ° C, luminous (except mercury)

Receiver

Photocells,

Photomultipliers,

Luminescent substances

History of discovery

Johann Ritter, Layman

Application

Industrial electronics and automation,

Fluorescent lamps,

Textile production

Air sterilization

Medicine, cosmetology

X-ray radiation

Wavelength(m)

10 -12 - 10 -8

Frequency Hz)

3∙10 16 - 3 · 10 20

Source

Electron X-ray tube (voltage at the anode - up to 100 kV, cathode - filament, radiation - high-energy quanta)

Solar corona

Receiver

Camera roll,

The glow of some crystals

History of discovery

V. Roentgen, R. Milliken

Application

Diagnostics and treatment of diseases (in medicine), Flaw detection (control internal structures, welds)

Gamma radiation

Wavelength(m)

3,8 · 10 -7 - 3∙10 -9

Frequency Hz)

8∙10 14 - 10 17

Energy(EV)

9,03 10 3 – 1, 24 10 16 Ev

Source

Radioactive atomic nuclei, nuclear reactions, processes of converting matter into radiation

Receiver

counters

History of discovery

Paul Villard (1900)

Application

Flaw detection

Process control

Research of nuclear processes

Therapy and diagnostics in medicine

GENERAL PROPERTIES OF ELECTROMAGNETIC RADIATIONS

physical nature

all radiation is the same

all radiations spread

in a vacuum at the same speed,

equal to the speed of light

all radiations are detected

general wave properties

polarization

reflection

refraction

diffraction

interference

• The entire scale of electromagnetic waves is evidence that all radiation has both quantum and wave properties.
• Quantum and wave properties in this case do not exclude, but complement each other.
• Wave properties appear more clearly at low frequencies and less clearly at high frequencies. Conversely, quantum properties appear more clearly at high frequencies and less clearly at low frequencies.
• The shorter the wavelength, the brighter the quantum properties appear, and the longer the wavelength, the brighter the wave properties appear.

• § 68 (read)
• fill in the last column of the table (effect of EMR on a person)
• prepare a report on the use of EMR