Communication arising between charged particles is called. Interaction of charged tel

Experiments of French Physics Sh. Dufe showed that the bodies having charges of the opposite (identical) sign are mutually attracted (repel). At the same time, the strength of the interaction between the electrified bodies is complexly depends on the shape of the electrified bodies and the nature of the distribution of charge on them. Therefore, there is no single simple formula describing electrostatic interaction for an arbitrary case.

Only for point charges The law of interaction is recorded in a fairly simple form.

The law of interaction of point electrical charges was opened in 1785. Sh. Pendant with strong scales. Cutting scales (Fig. 1) consist of two identical balls A and C; The ball A is reinforced on a rocker associated with a counterweight and thread L, the upper end of which is reinforced on a twisted head T. The ball from the device is reinforced on an isolated rod and is introduced inside the instrument. Balls A and C are given in contact, and since the balls are the same, then the ball charge with equally is distributed between them. Balls are repelled from each other. At the corner of twisting the threads determine the power of the interaction of charged balls. The distance R between the balls is measured on the scale applied on the side surface of the cylinder. Changing R and Q, Sh. Pendant found that

or, vector,

Unit vector. The interaction forces of the two of the same name of the charged balls are shown in Figure 2.

The strength of the interaction between two fixed point electric charges in a vacuum is directly proportional to the product of charge values, inversely proportional to the square of the distance between them and is directed along the straight line connecting these charges.

The law of the coulon is valid for charged balls at any distance between their centers, if the volume or surface density of the charge of each of them is constant. (Note that, in contrast to gravitational electrostatic interaction, it can lead to attraction and repulsion of tel.)

The coefficient of proportionality k \u003d 9 · 10 9 N · m 2 / CL 2. Often instead of k use another constant, called electrical constant

The laws of interaction of atoms and molecules can be understood and explained on the basis of knowledge about the structure of the atom using the planetary model of its structure. In the center of the atom there is a positively charged kernel, around which negatively charged particles rotate at certain orbits. The interaction between charged particles is called electromagnetic. The intensity of the electromagnetic interaction is determined by the physical value - electric charge, which is indicated by q. Unit of electric charge - pendant (CL). 1 pendant is such an electrical charge that, passing through the cross section of the conductor for 1 C, creates a current of the force of 1 A. The ability of electrical charges both to mutual attraction and to mutual repulsion is due to the existence of two types of charges. One type of charge called the positive, the carrier of the elementary positive charge is the proton. Another type of charge called the negative, its carrier is an electron. The elementary charge is equal to the particle charge is always represented by the number, a multiple of the elementary charge.

The full charge of the closed system (in which the charges are not included), i.e. the algebraic amount of charges of all bodies remains constant: Q1 + Q2 + ... + qn \u003d const. Electric charge is not created and does not disappear, but only moves from one body to another. This experimentally established fact is called the law of maintaining an electric charge. Never anywhere in nature arises and does not disappear electrical charge of one sign. The appearance and disappearance of electrical charges on bodies in most cases is due to the transitions of elementary charged particles - electrons - from some bodies to the other.

Electrification is a message body of an electric charge. Electrization can occur, for example, when contacting (friction) of heterogeneous substances and radiation. When electrifying in the body, an excess or disadvantage of electrons occurs.

In the case of excess electrons, the body acquires a negative charge, in the event of a shortage - positive.

The laws of interaction of fixed electric charges studies the electrostatics.

The main law of electrostatics was experimentally installed by the French physician Charlock Pendant and reads: the module of the interaction force of two point fixed electrical charges in vacuum is directly proportional to the product of the values \u200b\u200bof these charges and inversely proportional to the square of the distance between them.

R - the distance between them, k is the coefficient of proportionality, depending on the choice of system of units, in si

The value indicating how many times the strength of the interaction of charges in vacuum is greater than in the medium is called the dielectric permeability of the ED environment for the medium with dielectric constant E the law of the coulon is written as follows:

In the C coefficient K, it is customary to record as follows:

Electrical constant, numerically equal

The use of electrical permanent law of the coulon has the form:

The interaction of fixed electrical charges is called electrostatic or pendant interaction. Coulomb forces can be depicted graphically (Fig. 20, 21).

Definition 1.. The interaction of fixed electrical charges is called electrostatic or Coulomb interaction. The section of electrodynamics studying the Coulomb interaction is called electrostatic.

Definition 2.The interaction of charged bodies. Charges of the same sign are mutually repelled. The charges of a variety of sign are mutually attracted.

Electric charge is a physical quantity characterizing the property of particles or tel to join electromagnetic power interactions.

The law of conservation of an electric charge argues that in a closed system of bodies, the processes of birth or the disappearance of charges of only one sign can not be observed.

Electric field. Stroy field.

Definition 2.Electric field strength - vector physical quantity characterizing the electric field at a given point and numerically equal to the ratio of the power \\ VEC F acting on a fixed point charge placed at this point point to the magnitude of this charge Q:

Conductors and dielectrics in the electric field.

Definition 1.Conditions- These are substances characterized by the presence of a large number of free chargers in them, which are moved under the action of an electric field.

Definition 2.The dielectric (insulator) is a substance, practically non-conductive electrical current.

Permanent electric current. Current strength, tension, electrical resistance.

Definition 1.Permanent current, (Eng. Direct Current) - electric current, which over time does not change in size and direction.

Definition 2.The strength of the current in the conductor is a scalar value, numerically equal to the charge flowing per unit of time through the cross section of the conductor.

Definition 3. The voltage (U) is equal to the attitude of the electric field to move the charge to the magnitude of the charged charge on the chain section.

Electrical resistance (electroplating resistance) is a physical value that characterizes the properties of the conductor to prevent the passage of the electric current and equal to the ratio at the ends of the conductor to the current flowing through it

Electrostatics

Electric charge

The law of Kulon.

Cutting scales: Cutting scales

Electrodynamics

7. Electric shock Call an ordered movement of charged particles or charged macroscopic bodies. There are two types of electrical currents - conductivity currents and convection currents.

ELECTROMAGNETISM

14. (Magnetic field. Permanent magnets and magnetic field current)

A magnetic field - Power fieldoperating on moving electric charges and on bodies possessing magnetic moment, regardless of the state of their movement; magnetic Electromagnetic component field.

Permanent magnets Have two poles called the Northern and South Magnetic Fields. Between these poles, the magnetic field is located in the form of closed lines directed from the North Pole to the South. The magnetic field of the permanent magnet acts on metal objects and other magnets.

If you bring two magnets to each other with the poles of the same name, they will be repelled from each other. And if different, then attract. Magnetic lines of different charges at the same time as it were to be closed on each other.

If the metal object falls in the field of the magnet, the magnet magnetizes it, and the metal object itself becomes a magnet. It is attracted by its opposite pole to the magnet, so metal bodies are "sticking" to magnets.

A magnetic field It is created around electrical charges when they are moved. Since the movement of electrical charges is an electric current, then around every conductor with a current always exists tok magnetic field.

15. (Interaction of conductors with current. The power of the ampere)

The direction of the ampere force is determined by the rule of the left hand: if the left hand is positioned so that the perpendicular component of the magnetic induction vector in the palm, and the four elongated fingers were directed towards the current, then the thumb stranded 90 degrees will show the direction of force acting on the segment Conductor with a current, that is, the strength of the amper.

Newton's experiments

Experience on the decomposition of white light in the spectrum:

Newton sent a ray of sunlight through a small hole on a glass prism.
Finding on the prism, the beam was refracted and gave an extended image on the opposite wall with rainbow alternation of colors - spectrum.

Quantum optics.

Wave and corpuscular properties of light. Planck hypothesis about quanta. Photon.

I. Newton adhered to the so-called corpuscular theory of lightaccording to which the light is a flow of particles coming from the source in all directions (transfer of a substance).
Based on the corpuscular theory, it was difficult to explain why light beams crossing in space do not act on each other. After all, light particles must face and disperse.

The wave theory is easily explained. Waves, for example on the surface of the water, freely pass each other, without putting mutual influence.

However, the rectilinear spread of light, leading to the formation of the subjects of harsh shadows, is difficult to explain based on the wave theory. With the corpuscular theory, the rectilinear spread of light is simply a consequence of the law of inertia.

planck Ipectosis - It is an assumption that atoms emit electromagnetic energy (light) with separate portions - quanta, and not continuously.

Energy of each portion is a proportional radiation frequency:

where h \u003d 6.63 10 -34J C - is permanent Planck,

v. - It is the frequency of light.

Photon (γ ) - is an elementary particle, a quantum of electromagnetic radiation.

The emitting and absorbing light, behaves on the likeness of the flow of particles with an energy that depends on the frequency v.:

E.= hV,

where h. - is an standing Plan.

Photon energy Often express through the cyclic frequency Ω \u003d 2kVUsing instead h. magnitude ћ (read as "ASH with a feature"), which is equal ћ = h / 2π.. So, the photon energy can be expressed like this:

E \u003d HV \u003d ћΩ.

Based on the theory of relativity, the energy is associated with a mass ratio E \u003d MC 2. Since the photon energy is equal hVSo, his relativistic mass m P. equals:

Atomic and nuclear physics

33) The structure of the atom: the planetary model and the Bora model. Quantum postulates boron.

Absorption and emission of light atom. Energy quantization.

Atomic and nuclear physics - The physics section that studies the structure of the atom and the atomic nucleus and the processes associated with them.

Bor's postulates:1.The may be located in special quantum stationary states, each of which corresponds to its definite energy. In these states, the atom does not radiate (and does not absorb) energy.

two postulates.

1. A atom can be only in special, inpatient states. Each state corresponds to a certain value of energy - the energy level. Being in a stationary state, the atom does not radiate and does not absorb

Stationary states correspond to stationary orbits for which electrons moves. Rooms of stationary orbits and energy levels (starting from the first) are generally denoted by Latin letters: P, K, etc. The radii of orbits, as well as the energy of stationary states, can not receive any, but certain discrete values. The first orbit is located closest to the kernel.

2. The radiation of light occurs during the transition of an atom from a stationary state with a greater energy E to in a stationary state with less energy e n

According to the law of energy conservation, the energy of the emission photon is equal to the difference in the energy of stationary states:

hV \u003d E K - E N.

It follows from this equation that the atom can emit light only with frequencies

Atom can also absorb photons. When the photon is absorbed, the atom moves from a stationary state with less energy into a stationary state with greater energy. The presentation of an atom in which all electrons are located in stationary orbits with the lowest possible energy, is called the main. All other states of atom are called excited. The atoms of each chemical element have its own characteristic set of energy levels. Therefore, the transition from a higher energy level to the lower characteristic lines in the emission spectrum, different from the lines in the spectrum of another element. The lines of radiation lines and absorption in the spectra of atoms of this chemical element is explained by the fact that the frequencies of the waves corresponding to these lines in the spectrum, Determined by the same energy levels. Therefore, atoms can absorb only those frequencies that they can radiate.

Some physical quantities belonging to micro-lectures are not changed continuously, but scaly. On the values \u200b\u200bthat can only take well-defined, that is, discrete values \u200b\u200b(Latin "discrete" means separated, intermittent), they say that they are quantized. Electromagnetic radiation is emitted as separate portions - quantians - Energy. The value of one energy quanta is equal

Δ E. = h.ν,

where Δ. E. - the energy of Quantum, J; ν - frequency, C-1; h. - Permanent Planck (one of the fundamental constant nature), equal to 6.626 · 10-34 J · s.
Energy quanta subsequently called photons. Eye of the quantization of energy made it possible to explain the origin of the limited atomic spectra consisting of a set of lines combined in the series.
hydrogen.

Beta radiation

Beta radiation is electrons that are significantly less than alpha particles and can penetrate the body into several centimeters. From it can be protected by a thin sheet of metal, window glass and even ordinary clothing. Finding into unprotected parts of the body, beta radiation has an impact, as a rule, on the upper layers of the skin. During the accident at the Chernobyl nuclear power plant in 1986, firefighters received skin burns as a result of a very strong beta particle irradiation. If the substance emitting beta particles will fall into the body, it will irradiate inner tissues.

Gamma radiation

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

Radioactive decay occurs in accordance with the so-called offset rulesallowing to establish which core arises as a result of the collapse of this maternal nucleus. Displacement rules;

for a-decay

, (256.4)

for b-decay

, (256.5)

where - the parent kernel, Y is the character of the child core, the helium core (A-particle), is the symbolic indication of the electron (the charge of it is -1, and the mass number is zero). The displacement rules are nothing else, as a consequence of two laws performed in radioactive decays, the conservation of the electric charge and the preservation of the mass number: the sum of charges (mass numbers) of the emerging nuclei and particles is equal to the charge (mass number) of the source kernel.

Electrostatics

Interaction of charged bodies. Electric charge. The law of conservation of an electric charge.

What we had the opportunity to observe the experience with the attraction of pieces of paper to the electrical stick, proves the presence of electric interaction forces, and the magnitude of these forces characterizes such a thing as a charge. The fact that the power of electrical interaction can be different is easily checked by an experimental way, for example, when rubbing the same stick with different intensity. Electric charge - The physical value that characterizes the amount of interaction of charged bodies. Electrical charge conservation law: in an electrically closed system, the algebraic amount of charges is unchanged.Electrically closed system is a model. This is such a system that electric charges do not replenish and do not replenish.
History: The foundation of electrostatics put the works of Coulomb (although ten years before him the same results, even with even greater accuracy, received Cavendish. The results of the works of Cavendish were kept in the family archive and were published only after a hundred years); The law of electrical interactions found by the latest law enabled Green, Gauss and Poisson to create elegant in mathematically theory. The most significant part of electrostatics is the theory of potential created by the Green and Gauss. A very many experienced research on electrostatics was produced by the rice of the book of which were at the same time the main allowance in the study of these phenomena.

Faraday's experiments, made in the first half of the thirties of the XIX century, should have entail a fundamental change in the main provisions of the exercise on electrical phenomena. These experiments indicated that what was considered completely passively relating to electricity, namely, insulating substances or, as named pharades, dielectrics, is determining in all electrical processes and, in particular, in the electrification of conductors. These experiments found that the insulating layer meaning between the two surfaces of the capacitor plays an important role in the magnitude of the electric capacity of this capacitor.

Experiments with electrolytes: 1. If you take a solution of copper sulfate, collect an electrical chain and omit the electrodes (graphite rods from the pencil) into the solution, then the light bulb will light up. There is a current!
Repeat experience, replacing the electrode connected with the back of the battery on the aluminum button. After some time, it will become "golden", i.e. Cocks copper layer. This is the phenomenon of galvanotegia.

2. We will need: a glass with a sturdy salt solid, a battery from a pocket flashlight,
Two pieces of copper wire for about 10 cm. Clean the ends of the wire shallow emery skurt. Connect the battery to each pole one at the end of the wire. The free ends of the wire are lowered into a glass with a solution. Near the lowered ends of the wire raised bubbles!

The law of Kulon.

The law of Kulon.: The strength of the interaction of two charged bodies (the force of the Coulomb or Coulomb force) is directly proportional to the product of the modules of their charges and inversely proportional to the square of the distance between charges.

In the future, the law acquired the following final form:

History: For the first time to investigate experimentally, the law of interaction of electrically charged bodies offered G. V. Richman in 1752-1753. He intended to use the electrometer-"pointer" designed to this. The implementation of this plan was prevented by the tragic death of Richmana.

In 1759, Professor of Physics of the St. Petersburg Academy of Sciences F. Epinus, who took the Department of Richmana after his death, first suggested that the charges should interact inversely in proportion to the square square. In 1760, a brief report appeared that D. Bernoulli in Basel set a quadratic law using the electrometer constructed. In 1767, they were attracted in its "History of Electricity" noted that the experience of Franklin, who found the absence of an electric field inside the charged metal ball may mean that "The power of electric attraction is subject to the same laws as the strength of gravity, and therefore depends on the square of the distance between charges" . Scottish physicist John Robison argued (1822) that in 1769 discovered that the balls with the same electric charge are repelled with the force inversely in a proportional square of the distance between them, and thus anticipated the opening of the Culon law (1785).

Approximately 11 years before Coulomb, in 1771, the law of interaction of charges was experimentally opened by G. Cavendis, but the result was not published and for a long time (over 100 years) remained unknown. Manuscripts Cavendish were awarded to D. K. Maxwell only in 1874, one of the descendants of Cavendish at the solemn opening of the Cavendish laboratory and published in 1879.

The pendant himself was engaged in the study of the tight of the threads and invented the tweaks. He opened his law, measuring with the help of them the strength of the interaction of charged balls.

Cutting scales: Cutting scales - Physical instrument designed to measure small forces or moments of forces. Charlock pendant was invented in 1777 (according to other data, in 1784) to study the interaction of point electrical charges and magnetic poles. In the simplest version, the instrument consists of a vertical thread, which is suspended with a light balanced lever.

1. Recovery of charged bodies. The law of the coulon. The law of conservation of an electric charge.