“Electromagnetic oscillations” - Magnetic field energy. Option 1. Organizational stage. The reciprocal of capacitance, Radian (rad). Radian per second (rad/s). Option2. Fill out the table. The stage of generalization and systematization of the material. Lesson plan. Option 1 1.Which of the systems shown in the figure is not oscillatory? 3. Using the graph, determine a) the amplitude, b) the period, c) the frequency of oscillations. a) A. 0.2m B.-0.4m C.0.4m b) A. 0.4s B. 0.2s C.0.6s c) A. 5Hz B.25Hz C. 1.6Hz.

“Mechanical vibrations” - Wavelength (?) – the distance between nearby particles oscillating in the same phase. Harmonic vibration graph. Examples of free mechanical vibrations: Spring pendulum. Elastic waves are mechanical disturbances propagating in an elastic medium. Mathematical pendulum. Oscillations. Harmonic vibrations.

“Mechanical vibrations, grade 11” - There are waves: 2. Longitudinal - in which vibrations occur along the direction of propagation of the waves. Wave quantities: Visual representation of a sound wave. In a vacuum, a mechanical wave cannot arise. 1. Presence of an elastic medium 2. Presence of a source of vibrations - deformation of the medium.

“Small oscillations” - Wave processes. Sound vibrations. During the process of oscillations, kinetic energy is converted into potential energy and vice versa. Mathematical pendulum. Spring pendulum. The position of the system is determined by the deflection angle. Small fluctuations. The phenomenon of resonance. Harmonic vibrations. Mechanics. Equation of motion: m?l2???=-m?g?l?? or??+(g/l)??=0 Frequency and period of oscillation:

“Oscillatory systems” - External forces are forces acting on the bodies of the system from bodies not included in it. Oscillations are movements that are repeated at certain intervals. The friction in the system should be quite low. Conditions for the occurrence of free vibration. Forced vibrations are called vibrations of bodies under the influence of external periodically changing forces.

“Harmonic oscillations” - Figure 3. Ox – reference straight line. 2.1 Methods of representing harmonic vibrations. Such oscillations are called linearly polarized. Modulated. 2. The phase difference is equal to an odd number?, that is. 3. The initial phase difference is?/2. 1. The initial phases of oscillations are the same. The initial phase is determined from the relation.

Lesson objectives:

Lesson type:

Form: lecture with presentation

Karaseva Irina Dmitrievna, 17.12.2017

3355 349

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 students’ oral speech, students’ creative skills, 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"

Name radiation	Wavelength	Frequency	Who was open	Source	Receiver	Application	Effect on humans

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 is emitted by 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-rays 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), and images of various objects (radiolocation) are transmitted.

Radio waves are used to study the structure of matter and the properties of the medium in which they propagate. The study of radio emission from space objects is the 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. While studying the temperature rise of a thermometer heated by visible light, Herschel discovered the greatest heating of the thermometer outside the region of visible light (beyond the red region). Invisible 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. Infrared radiation accounts for a significant share (from 70 to 80%) of the radiation energy of incandescent lamps with tungsten filament. Infrared radiation is emitted by an 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 for drying wood, food and various paints and varnishes (infrared heating), for signaling in poor visibility, and makes it possible to use optical devices that allow you to see in the dark, as well as for remote control. Infrared rays are used to guide projectiles and missiles to targets and to detect camouflaged enemies. These rays make it possible to determine the difference in temperatures of individual areas of the surface of the planets, and 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. When exposed to humans, it causes an increase in the temperature of the 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 him. 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 wavelengths (frequencies) in the visible range has different physiological effects on 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 the electrochemical action of the human physiological system: 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 occurrence of 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. The absorption of carbon dioxide by plants as a result of the process of photosynthesis and the release of oxygen helps maintain biological life on Earth. 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. A more powerful source of ultraviolet radiation is any high-temperature plasma. For various applications of ultraviolet radiation, mercury, xenon and other gas-discharge lamps are used. Natural sources of ultraviolet radiation are the Sun, stars, nebulae and other space objects. However, only the long-wave part of their radiation (  290 nm) reaches the 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 the body's immune system, 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 (fraudulent documents can be detected from photographs), and in art history (with the help of ultraviolet rays, invisible traces of restoration can be detected in 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 - This is 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-ray radiation was discovered in 1895 by the German physicist W. K. Roentgen. 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-rays can be produced by bombarding a target with high-energy ions. Some radioactive isotopes and synchrotrons - electron storage devices - can also serve as sources of X-ray radiation. Natural sources of X-ray radiation are 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, a scintillation counter, secondary electron or channel electron multipliers, and microchannel plates. Due to its high penetrating ability, X-ray radiation is used in X-ray diffraction analysis (studying the structure of a crystal lattice), in studying the structure of molecules, detecting defects in samples, in medicine (X-rays, fluorography, treatment of cancer), in flaw detection (detection of defects in castings, rails) , in art history (discovery of ancient painting hidden under a layer of later painting), in astronomy (when studying X-ray sources), and forensic science. A large dose of X-ray radiation leads to burns and changes in the structure of human blood. The creation of X-ray receivers and their placement on space stations made it possible to detect X-ray radiation from hundreds of stars, as well as the shells of supernovae 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 radium radiation in a strong magnetic field, Villar discovered short-wave electromagnetic radiation that, like light, is not deflected by a 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 recorded using ionization and bubble chambers, as well as using special photographic emulsions. They are used in the study of nuclear processes and 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 common properties:

the physical nature of 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

UHF- 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 incandescent lamp

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 of 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

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Slide captions:

Electromagnetic wave scale. Types, properties and applications.

From the history of discoveries... 1831 - Michael Faraday established that any change in the magnetic field causes the appearance of an inductive (vortex) electric field in the surrounding space.

1864 – James Clerk Maxwell hypothesized the existence of electromagnetic waves capable of propagating in vacuum and dielectrics. Once the process of changing the electromagnetic field has begun at a certain point, it will continuously capture new areas of space. This is an electromagnetic wave.

1887 - Heinrich Hertz published the work “On Very Fast Electric Oscillations,” where he described his experimental setup - a vibrator and a resonator - and his experiments. When electrical vibrations occur in the vibrator, a vortex alternating electromagnetic field appears in the space around it, which is recorded by the resonator.

Electromagnetic waves are electromagnetic oscillations propagating in space with a finite speed.

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

Low-frequency oscillations Wavelength (m) 10 13 - 10 5 Frequency (Hz) 3 10 -3 - 3 10 3 Energy (EV) 1 – 1.24 10 -10 Source Rheostatic alternator, dynamo, Hertz vibrator, Generators in electrical networks (50 Hz) Machine generators of high (industrial) frequency (200 Hz) Telephone networks (5000 Hz) Sound generators (microphones, loudspeakers) Receiver Electrical devices and engines Discovery history Lodge (1893), Tesla (1983) Application Cinema, radio broadcasting (microphones, loudspeakers)

Radio waves are produced using oscillatory circuits and macroscopic vibrators. Properties: radio waves of different frequencies and with different wavelengths are absorbed and reflected differently by media. exhibit diffraction and interference properties. Wavelengths cover the region from 1 micron to 50 km

Application: Radio communications, television, radar.

Infrared radiation (thermal) Emitted by atoms or molecules of a substance. Infrared radiation is emitted by all bodies at any temperature. Properties: passes through some opaque bodies, as well as through rain, haze, snow, fog; produces a chemical effect (photoglastinki); being absorbed by a substance, it heats it up; invisible; capable of interference and diffraction phenomena; recorded by thermal methods.

Application: Night vision device, forensics, physiotherapy, in industry for drying products, wood, fruits

Visible radiation Properties: reflection, refraction, affects the eye, capable of dispersion, interference, diffraction. The portion of electromagnetic radiation perceived by the eye (red to violet). The wavelength range occupies a small interval from approximately 390 to 750 nm.

Ultraviolet radiation Sources: gas-discharge lamps with quartz tubes. It is emitted by all solids for which t 0> 1 000°C, as well as by luminous mercury vapor. Properties: High chemical activity, invisible, high penetrating ability, kills microorganisms, in small doses has a beneficial effect on the human body (tanning), but in large doses it has a negative effect, changes cell development, metabolism.

Application: in medicine, in industry.

X-rays are emitted at high electron accelerations. Properties: interference, X-ray diffraction on a crystal lattice, high penetrating power. Irradiation in large doses causes radiation sickness. Obtained using an X-ray tube: electrons in a vacuum tube (p = 3 atm) 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)

Application: In medicine for the purpose of diagnosing diseases of internal organs; in industry to control the internal structure of various products.

γ-radiation Sources: atomic nucleus (nuclear reactions). Properties: Has enormous penetrating power and has a strong biological effect. Wavelength less than 0.01 nm. Highest energy radiation

Application: In medicine, production (γ-flaw detection).

Impact of electromagnetic waves on the human body

Thank you for your attention!

1 of 27

Presentation on the topic: Electromagnetic vibrations

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get acquainted with the history of the discovery of electromagnetic oscillations get acquainted with the history of the discovery of electromagnetic oscillations get acquainted with the development of views on the nature of light gain a deeper understanding of the theory of oscillations find out how electromagnetic oscillations are used in practice learn to explain electromagnetic phenomena in nature generalize knowledge about electromagnetic oscillations and waves of various origins

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“Current is what creates a magnetic field” “Current is what creates a magnetic field” Maxwell first introduced the concept of field as a carrier of electromagnetic energy, which is discovered experimentally. Physicists discovered the bottomless depth of the fundamental idea of ​​Maxwell's theory.

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Electromagnetic waves were first obtained by G. Hertz in his classical experiments performed in 1888 - 1889. To excite electromagnetic waves, Hertz used a spark generator (Ruhmkorff coil). Electromagnetic waves were first obtained by G. Hertz in his classical experiments performed in 1888 - 1889. To excite electromagnetic waves, Hertz used a spark generator (Ruhmkorff coil).

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On March 24, 1896, at a meeting of the Physics Department of the Russian Physico-Chemical Society, A.S. Popov demonstrated the transmission of the world's first radiogram. On March 24, 1896, at a meeting of the Physics Department of the Russian Physico-Chemical Society, A.S. Popov demonstrated the transmission of the world's first radiogram. Here is what Professor O.D. Khvolson subsequently wrote about this historical event: “I was present at this meeting and clearly remember all the details. The departure station was located at the University's Chemical Institute, the receiving station was in the auditorium of the old physics office. Distance approximately 250m. The transmission took place in such a way that the letters were transmitted in the Morse alphabet and, moreover, the signs were clearly audible. The first message was "Heinrich Hertz."

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To transmit sound, for example, human speech, you need to change the parameters of the emitted wave, or, as they say, modulate it. Continuous electromagnetic oscillations are characterized by phase, frequency and amplitude. Therefore, to transmit these signals it is necessary to change one of these parameters. The most common is amplitude modulation, which is used by radio stations for the long, medium and short wave bands. Frequency modulation is used in transmitters operating on ultrashort waves. To transmit sound, for example, human speech, you need to change the parameters of the emitted wave, or, as they say, modulate it. Continuous electromagnetic oscillations are characterized by phase, frequency and amplitude. Therefore, to transmit these signals it is necessary to change one of these parameters. The most common is amplitude modulation, which is used by radio stations for the long, medium and short wave bands. Frequency modulation is used in transmitters operating on ultrashort waves.

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To reproduce the transmitted audio signal in the receiver, modulated high-frequency oscillations must be demodulated (detected). For this, nonlinear rectifying devices are used: semiconductor rectifiers or electron tubes (in the simplest case, diodes). To reproduce the transmitted audio signal in the receiver, modulated high-frequency oscillations must be demodulated (detected). For this, nonlinear rectifying devices are used: semiconductor rectifiers or electron tubes (in the simplest case, diodes).

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Natural sources of infrared radiation are: the Sun, Earth, stars, planets. Natural sources of infrared radiation are: the Sun, Earth, stars, planets. Artificial sources of infrared radiation are any body whose temperature is higher than the ambient temperature: a fire, a burning candle, a running internal combustion engine, a rocket, a switched on light bulb.

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many substances are transparent to infrared radiation many substances are transparent to infrared radiation when passing through the Earth’s atmosphere, they are strongly absorbed by water vapor; the reflectivity of many metals for infrared radiation is much greater than for light waves: aluminum, copper, silver reflect up to 98% of infrared radiation

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In industry, infrared radiation is used to dry painted surfaces and heat materials. For this purpose, a large number of different heaters have been created, including special electric lamps. In industry, infrared radiation is used to dry painted surfaces and heat materials. For this purpose, a large number of different heaters have been created, including special electric lamps.

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The most amazing and wonderful mixture The most amazing and wonderful mixture of colors is white. I. Newton And it all began, it would seem, with a purely scientific study of the refraction of light at the boundary of a glass plate and air, far from practice, a purely scientific study... Newton’s experiments not only laid the foundation for large areas of modern optics. They led Newton himself and his followers to a sad conclusion: in complex devices with a large number of lenses and prisms, white light necessarily turns into its beautiful colored components, and any optical invention will be accompanied by a mottled border, distorting the idea of ​​the object in question.

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Natural sources of ultraviolet radiation are the Sun, stars, and nebulae. Natural sources of ultraviolet radiation are the Sun, stars, and nebulae. Artificial sources of ultraviolet radiation are solids heated to temperatures of 3000 K and higher, and high-temperature plasma.

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Conventional photographic materials are used to detect and record ultraviolet radiation. To measure radiation power, bolometers with sensors sensitive to ultraviolet radiation, thermoelements, and photodiodes are used. Conventional photographic materials are used to detect and record ultraviolet radiation. To measure radiation power, bolometers with sensors sensitive to ultraviolet radiation, thermoelements, and photodiodes are used.

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Widely used in forensic science, art history, medicine, in production facilities of the food and pharmaceutical industries, poultry farms, and chemical plants. Widely used in forensic science, art history, medicine, in production facilities of the food and pharmaceutical industries, poultry farms, and chemical plants.

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It was discovered by the German physicist Wilhelm Roentgen in 1895. When studying the accelerated motion of charged particles in a discharge tube. The source of X-ray radiation is a change in the state of the electrons of the inner shells of atoms or molecules, as well as accelerated free electrons. The penetrating power of this radiation was so great that Roentgen could examine the skeleton of his hand on the screen. X-ray radiation is used: in medicine, in forensics, in industry, in scientific research. It was discovered by the German physicist Wilhelm Roentgen in 1895. When studying the accelerated motion of charged particles in a discharge tube. The source of X-ray radiation is a change in the state of the electrons of the inner shells of atoms or molecules, as well as accelerated free electrons. The penetrating power of this radiation was so great that Roentgen could examine the skeleton of his hand on the screen. X-ray radiation is used: in medicine, in forensics, in industry, in scientific research.

Slide no. 24

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Slide no. 25

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The shortest wavelength magnetic radiation, occupying the entire frequency range greater than 3 * 1020 Hz, which corresponds to wavelengths less than 10-12 m. It was discovered by the French scientist Paul Villard in 1900. It has even greater penetrating power than X-rays. It passes through a meter-thick layer of concrete and a layer of lead several centimeters thick. Gamma radiation occurs when a nuclear weapon explodes due to the radioactive decay of nuclei. The shortest wavelength magnetic radiation, occupying the entire frequency range greater than 3 * 1020 Hz, which corresponds to wavelengths less than 10-12 m. It was discovered by the French scientist Paul Villard in 1900. It has even greater penetrating power than X-rays. It passes through a meter-thick layer of concrete and a layer of lead several centimeters thick. Gamma radiation occurs when a nuclear weapon explodes due to the radioactive decay of nuclei.

Slide no. 26

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studying the history of the discovery of waves of different ranges allows us to convincingly show the dialectical nature of the development of views, ideas and hypotheses, the limitations of certain laws and at the same time the unlimited approach of human knowledge to the ever more intimate secrets of nature; studying the history of the discovery of waves of different ranges allows us to convincingly show the dialectical nature of the development of views , ideas and hypotheses, the limitations of certain laws and at the same time the unlimited approach of human knowledge to the ever more intimate secrets of nature, Hertz’s discovery of electromagnetic waves, which have the same properties as light, was decisive for the assertion that light is an electromagnetic wave analysis of information about the entire spectrum of electromagnetic waves allows us to create a more complete picture of the structure of objects in the Universe

Slide no. 27

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Kasyanov V.A. Physics 11th grade: Textbook. for general education Institutions. – 4th ed., stereotype. – M.: Bustard, 2004. – 416 p. Kasyanov V.A. Physics 11th grade: Textbook. for general education Institutions. – 4th ed., stereotype. – M.: Bustard, 2004. – 416 p. Koltun M.M. World of Physics: Scientific and artistic literature/Design by B. Chuprygin. – M.: Det. Lit., 1984. – 271 p. Myakishev G.Ya. Physics: Textbook. for 11th grade general education institutions. – 7th ed. – M.: Education, 2000. – 254 p. Myakishev G.Ya., Bukhovtsev B.B. Physics: Textbook. for 10th grade general education institutions. – M.: Education, 1983. – 319 p. Orekhov V.P. Oscillations and waves in a high school physics course. Manual for teachers. M., “Enlightenment”, 1977. – 176 p. I explore the world: Det. Encycl.: Physics/Under general. Ed. O.G. Hinn. – M.: TKO “AST”, 1995. – 480 p. www. 5ballov.ru

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