“Waves in the Ocean” - The devastating consequences of the Tsunami. Movement of the earth's crust. Learning new material. Find out objects on contour map. Tsunami. The length in the ocean is up to 200 km, and the height is 1 m. The height of the Tsunami off the coast is up to 40 m. Strait. V. Bay. Wind waves. Ebbs and flows. Wind. Consolidation of the studied material. The average speed of the Tsunami is 700 – 800 km/h.
"Waves" - "Waves in the ocean." They spread at a speed of 700-800 km/h. Guess which extraterrestrial object causes the tides to rise and fall? The highest tides in our country are at Penzhinskaya Bay in the Sea of Okhotsk. Ebbs and flows. Long gentle waves, without foamy crests, occurring in calm weather. Wind waves.
"Seismic waves" - Complete destruction. Felt by almost everyone; many sleepers wake up. Geographical distribution of earthquakes. Registration of earthquakes. On the surface of alluvium, subsidence basins are formed and filled with water. The water level in wells changes. Waves are visible on the earth's surface. There is no generally accepted explanation for such phenomena yet.
“Waves in a medium” - The same applies to a gaseous medium. The process of propagation of vibrations in a medium is called a wave. Consequently, the medium must have inert and elastic properties. Waves on the surface of a liquid have both transverse and longitudinal components. Consequently, transverse waves cannot exist in liquid or gaseous media.
“Sound waves” - The process of propagation of sound waves. Timbre is a subjective characteristic of perception, generally reflecting the characteristics of sound. Sound characteristics. Tone. Piano. Volume. Loudness - the level of energy in sound - is measured in decibels. Sound wave. As a rule, additional tones (overtones) are superimposed on the main tone.
“Mechanical waves, grade 9” - 3. By nature, waves are: A. Mechanical or electromagnetic. Plane wave. Explain the situation: There are not enough words to describe everything, The whole city is distorted. In calm weather, we are nowhere to be found, and when the wind blows, we run on the water. Nature. What "moves" in the wave? Wave parameters. B. Flat or spherical. The source oscillates along the OY axis perpendicular to OX.
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 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 spaceships. 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. 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). 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 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 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. According to their own physical properties it is similar to other ranges of the spectrum, 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 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 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 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 criminology (fraudulent documents can be detected from photographs), in art history (with the help of ultraviolet rays it is possible to detect in paintings not visible to the eye traces of restoration). 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 can also serve as sources of X-ray radiation. radioactive isotopes, synchrotrons are electron storage devices. 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. 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 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 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 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). TO dangerous species Radiations 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
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 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
Included in sunlight
Gas discharge lamps with quartz tube
Radiated by everyone solids, whose temperature is more 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
Control technological processes
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
11th grade student Klara Yeghyan
All information from stars, nebulae, galaxies and other astronomical objects comes in the form of electromagnetic radiation. Electromagnetic radiation scale. The horizontal axis shows: at the bottom - the wavelength in meters, at the top - the oscillation frequency in hertz
The Electromagnetic Wave Scale The electromagnetic wave scale extends from long radio waves to gamma rays. Electromagnetic waves of various lengths are conventionally divided into ranges according to various characteristics (method of production, method of registration, nature of interaction with matter).
Speed of light Any radiation can be considered as a stream of quanta - photons, propagating at the speed of light equal to c = 299,792,458 m/s. The speed of light is related to the wavelength and frequency by the relation c = λ ∙ ν
Spectrum of electromagnetic waves The spectrum of electromagnetic radiation in order of increasing frequency is: 1) Radio waves 2) Infrared radiation 3) Light radiation 4) X-rays 5) Gamma radiation The spectrum of electromagnetic waves is the frequency band of electromagnetic waves that exist in nature.
Radio waves Radio waves are electromagnetic waves whose lengths exceed 0.1 mm
Types of radio waves 1. Ultra-long waves with a wavelength greater than 10 km 2. Long waves in the length range from 10 km to 1 km 3. Medium waves in the length range from 1 km to 100 m
Types of radio waves (continued) 4. Short waves in the wavelength range from 100m to 10m 5. Ultrashort waves with a wavelength less than 10m
Infrared radiation Infrared radiation is electromagnetic waves that are emitted by any heated body, even if it does not glow. Infrared waves are also heat waves, because Many sources of these waves cause noticeable heating of surrounding bodies.
Light radiation Light radiation is a stream of radiant energy from the infrared, visible and ultraviolet regions of the spectrum, valid for several seconds, the source is the luminous area of the explosion.
X-ray radiation X-ray radiation occurs when fast charged particles (electrons, protons, etc.) decelerate, as well as as a result of processes occurring inside the electron shells of atoms. Application: medicine, physics, chemistry, biology, technology, forensics, art history
Gamma radiation Feature: pronounced corpuscular properties. Gamma radiation is a consequence of phenomena occurring inside atomic nuclei, as well as as a result of nuclear reactions.
Conclusion As the wavelength decreases, significant qualitative differences in electromagnetic waves appear. Radiations of different wavelengths differ from each other in the method of their production and the method of registration, that is, in the nature of their interaction with substances.
This presentation helps the teacher to more clearly conduct a lesson-lecture in 11th grade in physics when studying the topic “Radiations and Spectra”. Introduces students to various types spectra, spectral analysis, electromagnetic radiation scale.
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Slide captions:
Radiation and spectra Kazantseva T.R. physics teacher of the highest category MCOU Lugovskaya Secondary School of the Zonal District of the Altai Territory Lesson - lecture 11th grade
Everything we see is only one appearance, Far from the surface of the world to the bottom. Consider the obvious in the world to be unimportant, For the secret essence of things is not visible. Shakespeare
1. Introduce students to various types of radiation and their sources. 2. Show different types of spectra and their practical use. 3. Electromagnetic radiation scale. Dependence of radiation properties on frequency and wavelength. Lesson objectives:
Light sources Cold Hot electroluminescence photoluminescence cathodoluminescence fluorescent lamps discharge tubes St. Elmo's lights auroras glow of plasma TV screens phosphorus paints glow of CRT TV screens some deep-sea fish microorganisms Sun incandescent lamp flame fireflies corpse gases thermal xemiluminescence
This is radiation from heated bodies. Thermal radiation, according to Maxwell, is caused by vibrations electric charges in the molecules of matter that make up the body. Thermal radiation
Electroluminescence During a discharge in gases, the electric field imparts high kinetic energy to the electrons. Part of the energy goes to excite atoms. Excited atoms release energy in the form of light waves.
Cathodoluminescence The glow of solids caused by bombardment of them with electrons.
Chemiluminescence Radiation accompanying some chemical reactions. The light source remains cold.
Sergei Ivanovich Vavilov is a Russian physicist. Born on March 24, 1891 in Moscow, Sergei Vavilov began experiments on optics at the Institute of Physics and Biophysics - the absorption and emission of light by elementary molecular systems. Vavilov studied the basic laws of photoluminescence. Vavilov, his collaborators and students carried out the practical application of luminescence: luminescent analysis, luminescent microscopy, the creation of economical luminescent light sources, screens. Photoluminescence Some bodies themselves begin to glow under the influence of radiation incident on them. Glowing paints, toys, fluorescent lamps.
The density of emitted energy by heated bodies, according to Maxwell's theory, should increase with increasing frequency (with decreasing wavelength). However, experience shows that at high frequencies (short wavelengths) it decreases. A completely black body is a body that completely absorbs the energy incident on it. There are no absolutely black bodies in nature. Soot and black velvet absorb the most energy. Energy distribution in the spectrum
Instruments that can be used to obtain a clear spectrum, which can then be examined, are called spectral instruments. These include a spectroscope and spectrograph.
Types of spectra 2. Striped in the gaseous molecular state, 1. Lined in the gaseous atomic state, H H 2 3. Continuous or continuous bodies in the solid and liquid state, highly compressed gases, high-temperature plasma
A continuous spectrum is emitted by heated solids. The continuous spectrum, according to Newton, consists of seven regions - red, orange, yellow, green, blue, indigo and purple flowers. Such a spectrum is also produced by high-temperature plasma. Continuous spectrum
Consists of separate lines. Line spectra emit monatomic rarefied gases. The figure shows the spectra of iron, sodium and helium. Line spectrum
A spectrum consisting of individual bands is called a striped spectrum. Banded spectra are emitted by molecules. Striped spectra
Absorption spectra are spectra resulting from the passage and absorption of light in a substance. Gas absorbs most intensely the light of precisely those wavelengths that it itself emits in a highly heated state. Absorption spectra
Spectral analysis Atoms of any chemical element give a spectrum that is not similar to the spectra of all other elements: they are capable of emitting a strictly defined set of wavelengths. Determination method chemical composition substances according to its spectrum. Spectral analysis is used to determine the chemical composition of fossil ores during mining, to determine the chemical composition of stars, atmospheres, planets; is the main method for monitoring the composition of a substance in metallurgy and mechanical engineering.
Visible light is electromagnetic waves in the frequency range perceived by the human eye (4.01014-7.51014 Hz). Wavelengths from 760 nm (red) to 380 nm (violet). The range of visible light is the narrowest in the entire spectrum. The wavelength in it changes less than twice. Visible light accounts for the maximum radiation in the solar spectrum. During evolution, our eyes have adapted to its light and are able to perceive radiation only in this narrow part of the spectrum. Mars in visible light Visible light
Electromagnetic radiation, invisible to the eye in the wavelength range from 10 to 380 nm. Ultraviolet radiation can kill pathogenic bacteria, so it is widely used in medicine. Ultraviolet radiation in the composition of sunlight causes biological processes that lead to darkening of human skin - tanning. Gas-discharge lamps are used as sources of ultraviolet radiation in medicine. The tubes of such lamps are made of quartz, transparent to ultraviolet rays; That's why these lamps are called quartz lamps. Ultraviolet radiation
This is electromagnetic radiation invisible to the eye, the wavelengths of which are in the range from 8∙10 –7 to 10 –3 m Photograph of the head in infrared radiation Blue areas- colder, yellow - warmer. Areas of different colors differ in temperature. Infrared radiation
Wilhelm Conrad Roentgen - German physicist. Born on March 27, 1845 in the city of Lennep, near Düsseldorf. Roentgen was a major experimenter; he conducted many unique experiments for his time. Roentgen's most significant achievement was his discovery of X-rays, which now bear his name. This discovery by Roentgen radically changed the concept of the scale of electromagnetic waves. Beyond the violet boundary of the optical part of the spectrum and even beyond the boundary of the ultraviolet region, a region of even shorter wavelength electromagnetic radiation was discovered, further adjacent to the gamma range. X-rays
When X-ray radiation passes through a substance, the intensity of the radiation decreases due to scattering and absorption. X-rays are used in medicine to diagnose diseases and to treat certain diseases. X-ray diffraction allows one to study the structure of crystalline solids. X-rays are used to control the structure of products and detect defects.
The electromagnetic wave scale includes wide range waves from 10 -13 to 10 4 m. Electromagnetic waves are divided into ranges according to various characteristics (method of production, method of registration, interaction with matter) into radio and microwave waves, infrared radiation, visible light, ultraviolet radiation, x-rays and gamma rays . Despite the differences, all electromagnetic waves have common properties: they are transverse, their speed in vacuum is equal to the speed of light, they transfer energy, are reflected and refracted at the interface, exert pressure on bodies, their interference, diffraction and polarization are observed. Electromagnetic wave scale
Wave ranges and sources of their radiation
Thank you for your attention! Homework: 80, 84-86
Radio waves are produced using oscillating circuits and microscopic vibrators. They are obtained using oscillatory circuits and microscopic vibrators. 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. Properties:
Infrared radiation (thermal) Emitted by atoms or molecules of substances. passes through some opaque bodies, as well as through rain, haze, snow, fog; produces a chemical effect (photographic plates); being absorbed by a substance, it heats it up; invisible; capable of interference and diffraction phenomena; recorded by thermal methods. Properties: Application: Night vision device, forensics, physiotherapy, in industry for drying products, wood, fruits.
1000°C, as well as luminous mercury vapor. Properties: high chemical activity, invisibility, high penetrating ability" title=" Ultraviolet radiation Sources: gas-discharge lamps with quartz tubes. Emitted by all solids with t>1000°C, as well as luminous mercury vapor. Properties: high chemical activity, invisible, high penetrating power" class="link_thumb"> 5 !} Ultraviolet radiation Sources: gas-discharge lamps with quartz tubes. It is emitted by all solids with a temperature of >1000°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. 1000°C, as well as luminous mercury vapor. Properties: high chemical activity, invisible, high penetrating ability "> 1000 ° C, as well as 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."> 1000°C, as well as luminous mercury vapor. Properties: high chemical activity, invisibility, high penetrating ability" title=" Ultraviolet radiation Sources: gas-discharge lamps with quartz tubes. Emitted by all solids with t>1000°C, as well as luminous mercury vapor. Properties: high chemical activity, invisible, high penetrating power"> title="Ultraviolet radiation Sources: gas-discharge lamps with quartz tubes. It is emitted by all solids with a temperature of >1000°C, as well as by luminous mercury vapor. Properties: high chemical activity, invisible, high penetrating power"> !}
X-rays Sources: Emitted by high electron accelerations. Properties: interference, X-ray diffraction on a crystal lattice, high penetrating power. High dose radiation causes radiation sickness. Application: in medicine for the purpose of diagnosing diseases internal organs, in industry to control the internal structure of various products.
Gamma radiation Sources: atomic nucleus (nuclear reactions) Properties: has enormous penetrating ability, has a strong biological effect. Application: in medicine, manufacturing (gamma flaw detection) Application: in medicine, manufacturing (gamma flaw detection)
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11 Radio waves Wavelength (m) Frequency (Hz) Properties Radio waves are absorbed and reflected differently by media and exhibit interference and diffraction properties. Source Oscillatory circuit Macroscopic vibrators History of discovery Feddersen (1862), Hertz (1887), Popov, Lebedev, Rigi Application Ultra-long - Radio navigation, radiotelegraph communication, transmission of weather reports Long - Radiotelegraph and radiotelephone communication, radio broadcasting, radio navigation Medium - Radiotelegraphy and radiotelephone communications radio broadcasting, radio navigation Short-radio amateur communications VHF- space radio communications UHF- television, radiolocation, radio relay communications, cellular telephone communications SMV- radiolocation, radio relay communications, celestial navigation, satellite television MMV- radiolocation
12 Infrared radiation Wavelength (m), Frequency (Hz) Properties Passes through some opaque bodies, produces a chemical effect, invisible, capable of interference and diffraction, recorded by thermal methods Source Any heated body: candle, stove, radiator, electric incandescent lamp A person emits electromagnetic waves m long History of the discovery Rubens and Nichols (1896), Applications In forensics, 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 bodies cars, alarm system for premises security, infrared telescope,
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14 Visible radiation Wavelength (m)6, Frequency (Hz) Properties Reflection, refraction, affects the eye, capable of dispersion, interference, diffraction. Source Sun, incandescent lamp, fire Receiver Eye, photographic plate, photocells, thermoelements History of discovery Melloni Applications Vision Biological life
15 Ultraviolet radiation Wavelength (m) 3, Frequency (Hz) Properties High chemical activity, invisible, high penetrating ability, kills microorganisms, changes cell development, metabolism. Source Included in sunlight Gas-discharge lamps with a quartz tube Emitted by all solids whose temperature is greater than 1000 ° C, luminous (except mercury) Discovery history Johann Ritter, Leiman Applications Industrial electronics and automation, Fluorescent lamps, Textile production Air sterilization Medicine
16 X-ray radiation Wavelength (m) Frequency (Hz) Properties Interference, diffraction on a crystal lattice, high penetrating power Source Electron X-ray tube (voltage at the anode - up to 100 kV. pressure in the cylinder - 10-3 - 10-5 n/m2, cathode - incandescent filament. Anode material W, Mo, Cu, Bi, Co, Tl, etc. Η = 1-3%, radiation - high energy quanta) Solar corona History of discovery V. Roentgen, Millikan Application Diagnosis and treatment of diseases (in medicine) , Flaw detection (inspection of internal structures, welds)
17 Gamma radiation Wavelength (m) 3, Frequency (Hz) Properties Has enormous penetrating power, has a strong biological effect SourceRadioactive atomic nuclei, nuclear reactions, processes of converting matter into radiation Discovery history ApplicationDefectoscopy; Control of technological processes in production Therapy and diagnostics in medicine
