Around any conductor with current, i.e. moving electric charges, there is a magnetic field. The current should be considered as a source of a magnetic field! Around stationary electric charges there is only an electric field, and around moving charges - both electric and magnetic. HANS OERSTED ()

1. A magnetic field occurs only near moving electric charges. 2. It weakens as it moves away from a current-carrying conductor (or a moving charge) and it is impossible to indicate the exact boundaries of the field. 3. It acts on magnetic arrows in a certain way 4. It has energy and has its own internal structure, which is displayed using magnetic lines of force. The magnetic lines of the magnetic field of the current are closed lines covering the conductor

If the circuits with current are connected in series in one place in space, then such an formation is called a solenoid. The magnetic field is concentrated inside the solenoid, scattered outside, and the magnetic lines of force inside the solenoid are parallel to each other and the field inside the solenoid is considered to be uniform, outside the solenoid - inhomogeneous. By placing a steel rod inside the solenoid, we get the simplest electromagnet. Other things being equal, the magnetic field of an electromagnet is much stronger than the magnetic field of a solenoid.

Do the earth's magnetic poles coincide with the geographic poles? Has the location of the magnetic poles changed over the history of the planet? What is a reliable protector of life on Earth from cosmic rays? What is the reason for the appearance of magnetic storms on our planet? What are magnetic anomalies associated with? Why does the magnetic needle have a very definite direction in every place on the Earth? Where is she pointing?

Check yourself!!! Electric field around moving charges... Electric field around moving charges... Electric current -... Electric current -... Constant electric current -... Constant electric current -... Two conditions for occurrence electric current ... Two conditions for the occurrence of electric current ... Current strength - ... Current strength - ... Measure with an ammeter ... and include it in the circuit ... Measure with an ammeter ... and include it in circuit... They measure with a voltmeter... and turn it on... They measure it with a voltmeter... and turn it on... Current-voltage characteristic for metals... Current-voltage characteristic for metals... What determines the resistance of the conductor. .. What determines the resistance of a conductor... Ohm's Law... Ohm's Law... A charge equal to 20 C passes through the cross section of a conductor in 10 s. What is the current strength in the circuit? A charge equal to 20 C passes through the cross section of the conductor in 10 s. What is the current strength in the circuit? The mains voltage is 220V and the current is 2A. What resistance can a device that can be connected to this network have? The mains voltage is 220V and the current is 2A. What resistance can a device that can be connected to this network have?

Task 2 Determine the resistance of the circuit section, when connected at points B and D, if R1=R2=R3=R4=2 Ohm Determine the resistance of the circuit section, when connected at points B and D, if R1=R2=R3=R4=2 Ohm Will the resistance of the circuit section change when connected at points A and C? Will the resistance of the circuit section change when connected at points A and C? Given: R1=2 ohm R2=2 ohm R3=2 ohm R4=2 ohm Find: Rob-? Solution: R1.4=R1+R4, R1.4=2+2=4 (Ohm) R2.3=R2+R3, R2.3=2+2=4 (Ohm) 1/Rob= 1/R1, 4+ 1/R2.3, 1\Rob=1/4+1/4=1/2 Rob=2 (Ohm) Answer: Rob=2 Ohm.

Given: R1=0.5 ohmR2=2 ohmR3=3.5 ohmR4=4 ohmRob=1 ohm Given: R1=0.5 ohmR2=2 ohmR3=3.5 ohmR4=4 ohmRob=1 ohm Determine the connection method. Determine connection method. Solution: R1,3=R1+R3, R1,3=0.5+3.5=4(Ω) R1,3,4=...; R1,3,4=2 (Ohm) Rob=1 (Ohm) So R1,3 is in series, R1,3 and R4 are in parallel, R1,3,4 and R2 are in parallel.

Consider how 1,2,3 resistors are connected? Can we calculate Rv for them? 1/R I =1/R 1 +1/R 2 +1/R 3 ; R I \u003d 1 Ohm. Now look how these three resistors are connected to the fourth? So I can replace 1,2,3 resistors with one resistance R I =1 Ohm, which is equivalent to three resistors connected in parallel. What would be the wiring diagram then? Draw her. How to find total resistance now? R About =R I +R 4 ; R About \u003d 1 Ohm +5 Ohm \u003d 6 Ohm Now it remains to solve the question of what is the total current strength with such a connection? I about \u003d I \u003d I 4, therefore Uob \u003d 5 A * 6 Ohm \u003d 30 V Let's write down the answer to the problem.

> > R 3.4 = 1 ohm. R about - ? U AB - ? 2. Let's move on to the equivalent circuit 3. R 1, R 2 and R 3.4 are connected in series > R about = R 1 + R 2 + R 3.4 > R about = 5 Ohm 4. U AB "title =" (! LANG: Given: R 1 \u003d R 2 \u003d R 3 \u003d R 4 \u003d 2 ohms I \u003d 6 A Solution: 1.R 3 and R 4 are connected in parallel,\u003e\u003e\u003e R 3.4 \u003d 1 Ohm. R about -? U AB -?" class="link_thumb"> 13 !} Given: R 1 \u003d R 2 \u003d R 3 \u003d R 4 \u003d 2 Ohm I \u003d 6 A Solution: 1. R 3 and R 4 are connected in parallel,\u003e\u003e R 3.4 \u003d 1 Ohm. R about - ? U AB - ? 2. Let's move on to the equivalent circuit 3. R 1, R 2 and R 3.4 are connected in series > R about = R 1 + R 2 + R 3.4 > R about = 5 Ohm 4. U AB \u003d U 1 + U 2 + U 3.4, where, > or > U AB \u003d 6 A 5 Ohm \u003d 30 V Answer: U AB \u003d 30 V > > R 3.4 = 1 ohm. R about - ? U AB - ? 2. Let's move on to the equivalent circuit 3. R 1, R 2 and R 3.4 are connected in series> R about \u003d R 1 + R 2 + R 3.4> R about \u003d 5 Ohm 4. U AB ">>> R 3 ,4 \u003d 1 ohm R about - ? U AB - ? about \u003d 5 Ohm 4. U AB \u003d U 1 + U 2 + U 3.4, where,\u003e or\u003e U AB \u003d 6 A 5 Ohm \u003d 30 V Answer: U AB \u003d 30 V "\u003e\u003e\u003e R 3, 4 =1 ohm. R about - ? U AB - ? 2. Let's move on to the equivalent circuit 3. R 1, R 2 and R 3.4 are connected in series > R about = R 1 + R 2 + R 3.4 > R about = 5 Ohm 4. U AB "title =" (! LANG: Given: R 1 \u003d R 2 \u003d R 3 \u003d R 4 \u003d 2 ohms I \u003d 6 A Solution: 1.R 3 and R 4 are connected in parallel,\u003e\u003e\u003e R 3.4 \u003d 1 Ohm. R about -? U AB -?"> title="Given: R 1 \u003d R 2 \u003d R 3 \u003d R 4 \u003d 2 Ohm I \u003d 6 A Solution: 1. R 3 and R 4 are connected in parallel,\u003e\u003e R 3.4 \u003d 1 Ohm. R about - ? U AB - ? 2. Let's move on to the equivalent circuit 3. R 1, R 2 and R 3.4 are connected in series> R about \u003d R 1 + R 2 + R 3.4> R about \u003d 5 Ohm 4. U AB"> !}

Horizontally: 1. A negatively charged particle that is part of an atom. 2. Neutral particle, which is part of the atomic nucleus. 3. A physical quantity that characterizes the resistance exerted by a conductor to an electric current. 4. Unit of electric charge. 5. A device for measuring current strength. 6. A physical quantity equal to the ratio of the work of the current to the transferred charge. Vertically: 1. The process of imparting an electric charge to the body. 2. A positively charged particle that is part of the atomic nucleus. 3. Unit of voltage. 4. Unit of resistance. 5. An atom that has gained or lost an electron. 6. Directed motion of charged particles. 6. Directed motion of charged particles.

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 a magnetic field, this charge will have less energy.

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 be spent on electromagnetic radiation directed into infinite space, which will not return as self-induction when it stops. 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 tracked in a moving and stationary physical body, which does not have 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, in addition to the electric field, a magnetic field also appears around the moving sphere, as in the case of a charge. Therefore, in order to do work, the speed for a charged sphere will require more than for 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.

To the question The magnetic field is formed by a moving charge? given by the author I-beam the best answer is Everything is exactly like that. Movement is relative. Therefore, the magnetic field will be observed in the system relative to which the charge moves. To get a magnetic field, the movement of two oppositely charged particles is not at all necessary. It's just that when current flows in conductors, charges are compensated and weaker (compared to electrostatic) magnetic effects come to the fore.
Calculations for the derivation of the equations of magnetic fields from SRT and the Coulomb field can be found in any textbook on electrodynamics. For example, in the Feynman Lectures on Physics, v. 5 (Electricity and Magnetism) Chap. 13 (Magnetostatics) in §6 this question is considered in detail.
The tutorial can be found at http:// lib. homelinux. org/_djvu/P_Physics/PG_General courses/Feynman/Fejnman R., R.Lejton, M.Se"nds. Tom 5. E"lektrichestvo i Magnetizm (ru)(T)(291s).djvu
There are many interesting things in the 6th volume (Electrodynamics).
http:// lib. homelinux. org/_djvu/P_Physics/PG_General courses/Feynman/Fejnman R., R.Lejton, M.Se"nds. Tom 6. E"lektrodinamika (ru)(T)(339s).djvu
(remove only extra spaces in the site address)
And the radiation and the magnetic field from a charged wand that you are waving will be small not because of the speed, but because of the insignificance of the charge (and the magnitude of the current created by the movement of such a small charge - you can calculate for yourself).

Answer from percolate[guru]
The very concept of motion is relative. Therefore, yes, in one coordinate system there will be a magnetic field, in another it will be different, in the third it will not be at all. In fact, there is no magnetic field at all, it's just that the effects of the special theory of relativity for moving charges are conveniently described by introducing a fictitious field, called magnetic, which greatly simplifies calculations. Before the advent of the theory of relativity, the magnetic field was considered an independent entity, and only then it was established that the forces attributed to it are perfectly calculated even without it on the basis of the theory of relativity and Coulomb's law. But, of course, the theory of relativity is much more difficult to apply in practice than the gimlet rule 😉 And since the electric and magnetic fields are closely related (although the second is a visual interpretation of the consequences of changes in the first), they talk about a single electromagnetic field.
And as for running around the room with a charged wand, there is no need for the theory of relativity - of course, a magnetic field is formed, waves are emitted, and so on, only very weak ones. Calculating the intensity of the created field is a task for the student.

Answer from conscience[guru]
Well, again, I smoked in the toilet instead of physics ... Is the textbook hard to open? It clearly says "electromagnetic field" and so on and so forth. Lisapets love to compose and invent perpetual motion machines. On torsion fields..

Answer from VintHeXer[active]
In general, IMHO, according to Ampère's law and some other very clever formula that has the sine of the angle in the record, already shows that you need the movement of a charged particle in the conductor (again IMHO), since the current will be at voltage and resistance ... The voltage seems to be as it is (the particle is charged), but the resistance in a vacuum ...
In general, who the hell knows... Especially about the motion of a charged particle in a vacuum))

Answer from Krab Bark[guru]
Well, a detailed conclusion must be sought in physics textbooks. This can be downloaded, for example, here :)
"albeit with your help - but the children will gradually deduce the magnetic attraction or repulsion of currents in electrically neutral conductors from Coulomb's law and the theory of relativity. For them, this will be a miracle created by their own hands. More is not required in high school. At the university, they will casually explain how from the Coulomb's law for fixed charges and the formulas for the transformation of quadratic differential forms in the theory of relativity follow the equations of electromagnetic fields of Maxwell. "
In general, in such matters it is necessary to put a tick in the field for the possibility of making comments ...

Magnetic field on Wikipedia
Check out the wikipedia article on the magnetic field

The magnetic field of a moving charge can arise around a current-carrying conductor. Since electrons with an elementary electric charge move in it. It can also be observed when other charge carriers move. For example, ions in gases or liquids. This ordered movement of charge carriers, as is known, causes the appearance of a magnetic field in the surrounding space. Thus, it can be assumed that a magnetic field, regardless of the nature of the current causing it, also arises around a single charge in motion.

The general field in the environment is formed from the sum of the fields created by individual charges. This conclusion can be drawn from the principle of superposition. Based on various experiments, a law was obtained that determines the magnetic induction for a point charge. This charge moves freely in the medium at a constant speed.

Formula 1 - the law of electromagnetic induction for a moving point charge

Where r radius vector from the charge to the point of observation

Q charge

V charge velocity vector

Formula 2 - modulus of the induction vector

Where alpha is the angle between the velocity vector and the radius vector

These formulas determine the magnetic induction for a positive charge. If it is necessary to calculate it for a negative charge, then you need to substitute the charge with a minus sign. The speed of the charge is determined relative to the point of observation.

To detect a magnetic field when moving a charge, you can conduct an experiment. In this case, the charge does not have to move under the action of electric forces. The first part of the experiment is that an electric current passes through a circular conductor. Therefore, a magnetic field is formed around it. The action that can be observed when the magnetic needle is deflected next to the coil.

Figure 1 - a circular coil with current acts on a magnetic needle

The figure shows a coil with current, the plane of the coil is shown on the left, the plane perpendicular to it is shown on the right.

In the second part of the experiment, we will take a solid metal disk fixed on an axis from which it is isolated. In this case, the disk is given an electric charge, and it is able to quickly rotate around its axis. A magnetic needle is fixed above the disk. If you spin the disk with a charge, you can find that the arrow is rotating. Moreover, this movement of the arrow will be the same as when the current moves through the ring. If at the same time you change the charge of the disk or the direction of rotation, then the arrow will also deviate in the other direction.