Around the moving electric charges exist. Magnetic field, its properties. Einstein's ideas and ether

Creates around itself, is more complex than what is characteristic of a charge that is in a stationary state. In the ether, where space is not perturbed, the charges are balanced. Therefore, it is called magnetically and electrically neutral.

Let us consider in more detail the behavior of such a charge separately, in comparison with a stationary one, and think about Galileo's principle, and at the same time about Einstein's theory: how consistent is it really?

The difference between moving and stationary charges

A single charge, being motionless, creates an electric field, which can be called the result of the deformation of the ether. And a moving electric charge creates both electric and It is detected only by another charge, that is, by a magnet. It turns out that the resting and moving charges in the ether are not equivalent to each other. With uniform and charge will not radiate and will not lose energy. But since part of it is spent on creating magnetic field, then the energy of this charge will be less.

An example to make it easier to understand

This is easier to imagine with an example. If you take two identical stationary charges and place them far apart so that the fields cannot interact, one of them will be left as is, and the other will be moved. For an initially stationary charge, acceleration will be required, which will create a magnetic field. Part of the energy of this field will go to electromagnetic radiation, directed into infinite space, which will not return as a self-induction when stopped. With the help of another part of the charging energy, a constant magnetic field will be created (assuming a constant charge rate). This is the energy of ether deformation. At , the magnetic field remains constant. If at the same time two charges are compared, then the moving one will have a smaller amount of energy. It's all because of the moving charge, on which he has to spend energy.

Thus, it becomes clear that in both charges the state and energy are very different. The electric field acts on stationary and moving charges. But the latter is also affected by the magnetic field. Therefore, it has less energy and potential.

Moving charges and Galileo's principle

The state of both charges can also be traced in a moving and stationary physical body, which has no moving charged particles. And Galileo's principle here can be objectively proclaimed: a physical and electrically neutral body that moves uniformly and rectilinearly is indistinguishable from that which is at rest with respect to the Earth. It turns out that bodies neutral to electricity and charged ones manifest themselves differently at rest and in motion. Galileo's principle cannot be used in the ether and cannot be applied to mobile and immobile charged bodies.

Inconsistency of the principle for charged bodies

A lot of theories and works about those fields that create a moving electric charge have accumulated today. For example, Heaviside showed that the electric vector formed by the charge is radial everywhere. The magnetic lines of force, which are formed by a point charge during movement, are circles, and in their centers there are lines of movement. Another scientist, Searle, solved the problem of the distribution of charge in a sphere in motion. It was found that it generates a field similar to that which a moving electric charge creates, despite the fact that the latter is not a sphere, but a compressed spheroid, in which the polar axis is directed in the direction of motion. Later, Morton showed that in an electrified sphere in motion, the density on the surface would not change, but the lines of force would no longer leave it at an angle of 90 degrees.

The energy surrounding the sphere becomes greater when it moves than when the sphere is at rest. This is because apart from electric field, a magnetic field also appears around the moving sphere, as in the case of a charge. Therefore, in order to do work, a charged sphere will need a greater speed than one that is electrically neutral. Together with the charge, the effective mass of the sphere also increases. The authors are sure that this is due to the self-induction of the convection current that the moving electric charge creates from the beginning of the movement. Thus, Galileo's principle is recognized as untenable for bodies charged with electricity.

Einstein's ideas and ether

Then it becomes clear why Einstein did not assign a place to the ether in SRT. After all, the very fact of recognizing the presence of the ether already destroys the principle, which consists in the equivalence of inertial and independent frames of reference. And he, in turn, is the basis of SRT.

Each conductor with current creates a magnetic field in the surrounding space. Electric current is an ordered movement electric charges. Therefore, we can say that any charge moving in a vacuum or medium creates a magnetic field around itself. As a result of generalization of experimental data

a law was established that determines the field B of a point charge Q, freely moving with a nonrelativistic speed v. Under the free movement of charge is understood to be moving at a constant speed. This law is expressed by the formula

where r is the radius vector drawn from the charge Q to the observation point M(Fig. 168). According to expression (113.1), the vector B is directed perpendicular to the plane in which the vectors v and r are located, namely: its direction coincides with the direction of the translational movement of the right screw when it rotates from v to r. The magnetic induction modulus (113.1) is calculated by the formula

where a is the angle between the vectors v and r.

Comparing expressions (110.1) and (113.1), we see that the moving charge in its magnetic properties is equivalent to the current element:

I d l=Q v.

The above regularities (113.1) and (113.2) are valid only at low speeds (v<

Formula (113.1) determines the magnetic induction of a positive charge moving at a speed v. If a negative charge is moving, then Q should be replaced with - Q. Speed ​​v - relative

relative speed, i.e., speed relative to the observer. Vector AT in the reference frame under consideration depends both on time and on the position of the point M observations. Therefore, the relative nature of the magnetic field of a moving charge should be emphasized.

For the first time, the field of a moving charge was discovered by the American physicist G. Rowland (1848-1901). This fact was finally established by the professor of Moscow University A. A. Eikhenwald (1863-1944), who studied the magnetic field of the convection current, as well as the magnetic field of the bound charges of a polarized dielectric. The magnetic field of freely moving charges was measured by Academician A.F. Ioffe, who proved the equivalence, in terms of magnetic field excitation, of an electron beam and conduction current.

§114. The action of a magnetic field on a moving charge

Experience shows that a magnetic field acts not only on conductors with current (see § 111), but also on individual charges moving in a magnetic field. Force acting on an electric charge Q moving in a magnetic field with a speed v is called Lorentz force and is expressed by the formula

F=Q[vB], (114.1) where B is the induction of the magnetic field in which the charge moves.

The direction of the Lorentz force is determined using left hand rules: if the palm of the left hand is positioned so that it includes the vector B, and four outstretched fingers are directed along the vector v (for Q> 0 directions I and v are the same, for Q<0-противоположны), то отогнутый большой палец покажет направление силы, действующей на positive charge. On fig. 169 shows the mutual orientation of the vectors v, B (the field is directed towards us, shown by dots in the figure) and F for a positive charge. On a negative charge, the force acts in the opposite direction.

The Lorentz force modulus (see (114.1)) is equal to

F=QvB sin,

where  is the angle between v and AT.

We note again (see § 109) that the magnetic field does not act on a resting electric charge. This is the essential difference between a magnetic field and an electric field. A magnetic field only acts on charges moving in it.

Since the magnitude and direction of the vector B can be determined from the action of the Lorentz force, the expression for the Lorentz force can be used (along with others, see § 109) to determine the magnetic induction vector B.

The Lorentz force is always perpendicular to the velocity of the charged particle, so it only changes the direction of this velocity without changing its modulus. Therefore, the Lorentz force does no work. In other words, a constant magnetic field does no work on a charged particle moving in it, and the kinetic energy of this particle does not change when moving in a magnetic field.

If, in addition to a magnetic field with induction B, a moving electric charge is also affected by an electric field with strength E, then the resulting force F, applied to the charge, is equal to the vector sum of forces - the force acting from the electric field, and the Lorentz force:

F=QE + Q[vB].

This expression is called Lorentz formula. The speed v in this formula is the speed of the charge relative to the magnetic field.

1. An electromagnetic field is a kind of matter that arises around moving charges. For example, around a conductor with current. The electromagnetic field consists of two components - electric and magnetic fields. They cannot exist independently of each other. One begets the other. When the electric field changes, a magnetic field immediately arises. An electromagnetic wave propagates in space in all directions from its source. You can imagine turning on a light bulb, the rays of light from it spread in all directions. An electromagnetic wave during propagation carries energy in space. The stronger the current in the conductor that caused the field, the greater the energy carried by the wave. Also, the energy depends on the frequency of the emitted waves, with an increase in it by 2.3.4 times, the energy of the wave will increase by 4.9.16 times, respectively. That is, the propagation energy of the wave is proportional to the square of the frequency.

2. Filter in electronics, a device for isolating desirable components of an electrical signal spectrum and/or suppressing unwanted ones. Filters that find application in signal processing are

analog or digital

passive or active

linear and non-linear

recursive and non-recursive

Among the many recursive filters, the following filters are separately distinguished (according to the type of transfer function):

Chebyshev filters

bessel filters

Butterworth filters

elliptical filters

According to what frequencies the filter passes (delays), the filters are divided into

low pass filters (LPF)

high pass filters (HPF)

band pass filters (BPF)

band-stop (notch) filters (BPF)

phase filters

Filter classification

In constructions passive analog filters use lumped or distributed reactive elements such as inductors and capacitors. The resistance of reactive elements depends on the frequency of the signal, therefore, by combining them, it is possible to achieve amplification or attenuation of harmonics with the desired frequencies. Active analog filters are based on amplifiers covered by a feedback loop (positive or negative). In active filters, it is possible to avoid the use of inductors, which makes it possible to reduce the physical dimensions of devices, simplify and reduce the cost of their manufacture.

3. Electric generator- a device in which non-electrical forms of energy (mechanical, chemical, thermal) are converted into electrical energy. Classification of electromechanical generators

By type of prime mover:

Turbogenerator - an electrical generator driven by a steam turbine or gas turbine engine;

Hydrogenerator - an electric generator driven by a hydraulic turbine;

Diesel generator - an electric generator driven by a diesel engine;

Wind generator - an electric generator that converts the kinetic energy of the wind into electricity;

According to the type of output electric current

Three-phase generator

With the inclusion of star windings

With the inclusion of windings in a triangle

By way of excitation

With permanent magnet excitation

with external stimulation

With self-excitation

With sequential excitation

With parallel excitation

With mixed excitement.

The simplest DC generator is a frame of conductor placed between the poles of a magnet, the ends of which are attached to insulated half rings called collector plates. Positive and negative brushes are pressed against the half-rings (collector), which are closed by an external circuit through an electric light bulb. For the generator to work, the conductor frame with the collector must be rotated. In accordance with the right-hand rule, when the frame of the conductor with the collector rotates, an electric current will be induced in it, changing its direction every half a turn, since the magnetic lines of force on each side of the frame will intersect first in one direction, then in the other direction. Along with this, every half-turn, the contact of the ends of the conductor of the frame and the semi-rings of the collector with the brushes of the generator changes. In the external circuit, the current will flow in one direction, changing only in magnitude from 0 to a maximum. Thus, the collector in the generator serves to rectify the alternating current generated by the loop. In order for the electric current to be constant not only in direction, but also in magnitude (in magnitude - approximately constant), the collector is made of many (36 or more) plates, and the conductor is a lot of frames or sections made in the form of an armature winding . 1 - electromagnet pole; 2 - excitation coil; 3 - contact ring; 4 - generator brush; S - external circuit; 6 - conductor frame; 7 - direct current source.

Electric field- this is a special form of matter, through which the interaction of electrically charged particles is carried out.

The introduction of the concept of electric field was needed to explain the interaction of electric charges, i.e., to answer the questions: why do forces arise that act on charges, and how are they transferred from one charge to another?

The concepts of electric and magnetic fields were introduced by the great English physicist Michael Faraday. According to Faraday's idea, electric charges do not act directly on each other. Each of them creates in the surrounding space electric field. The field of one charge acts on another charge, and vice versa. As you move away from the charge, the field weakens.

With the introduction of the field concept in physics, the short range theory, the main difference of which from the long-range theory is the idea of ​​the existence of a certain process in space between interacting bodies, which lasts a finite time.

This idea was confirmed in the works of the great English physicist J.K. Maxwell, who theoretically proved that electromagnetic interactions should propagate in space with a finite speed - With, equal to the speed of light in vacuum (300,000 km/s). Experimental proof of this statement was the invention of the radio.

An electric field arises in the space surrounding a stationary charge, in the same way as a magnetic field arises around moving charges - currents or permanent magnets. Magnetic and electric fields can turn into each other, forming a single electromagnetic field. The electric field (as well as the magnetic one) is only a special case of the general electromagnetic field. Variable electric and magnetic fields can exist without the charges and currents that generated them. An electromagnetic field carries a certain amount of energy, as well as momentum and mass. Thus, the electromagnetic field is a physical entity that has certain physical properties.

So, nature of the electric field consists of the following:

1. The electric field is material, it exists independently of our consciousness.

2. The main property of the electric field is its action on electric charges with a certain force. By this action, the fact of its existence is established. The action of the field on a unit charge is field strength- is one of its main characteristics, according to which the distribution of the field in space is studied.

The electric field of stationary charges is called electrostatic. It does not change over time, is inextricably linked with the charges that gave rise to it, and exists in the space surrounding them.