What is the shape of the magnetic field lines. What are magnetic field lines
A magnetic field - power field , acting on moving electric charges and on bodies with magnetic moment, regardless of the state of their movement;magnetic component of the electromagnetic fields .
lines of force magnetic field- these are imaginary lines, the tangents to which at each point of the field coincide in direction with the magnetic induction vector.
For a magnetic field, the principle of superposition is valid: at each point in space, the vector of magnetic induction B∑ → B∑→created at this point by all sources of magnetic fields is equal to vector sum magnetic induction vectors bk→ Bk→created at this point by all sources of magnetic fields:
28. Law of Biot-Savart-Laplace. Full current law.
The formulation of Biot Savart Laplace's law is as follows: When passing direct current along a closed loop in vacuum, for a point at a distance r0 from the loop, the magnetic induction will have the form.
where I current in the circuit
gamma contour along which the integration is carried out
r0 arbitrary point
Full current law this is the law relating the circulation of the magnetic field strength vector and the current.
The circulation of the magnetic field strength vector along the circuit is equal to the algebraic sum of the currents covered by this circuit.
29. Magnetic field of a conductor with current. Magnetic moment of circular current.
30. The action of a magnetic field on a conductor with current. Ampere's law. Interaction of currents .
F = B I l sinα ,
where α - the angle between the vectors of magnetic induction and current,B - magnetic field induction,I - current in the conductor,l - conductor length.
Interaction of currents. If two wires are included in the DC circuit, then: Closely spaced parallel conductors connected in series repel each other. Conductors connected in parallel attract each other.
31. Action of electric and magnetic fields on a moving charge. Lorentz force.
Lorentz force - strength, with which electromagnetic field according to the classical (non-quantum) electrodynamics acts on point charged particle. Sometimes the Lorentz force is called the force acting on a moving with a speed charge only from the side magnetic field, often full force- from the side of the electromagnetic field in general , in other words, from the side electric and magnetic fields.
32. The action of a magnetic field on matter. Dia-, para- and ferromagnets. Magnetic hysteresis.
B= B 0 + B 1
where B⃗ B → - magnetic field induction in matter; B⃗ 0 B→0 - magnetic field induction in vacuum, B⃗ 1 B→1 - magnetic induction of the field that arose due to the magnetization of the substance.
Substances for which the magnetic permeability is slightly less than unity (μ< 1), называются diamagnets, slightly greater than one (μ > 1) - paramagnets.
ferromagnet - the substance or material in which the phenomenon is observed ferromagnetism, i.e., the appearance of spontaneous magnetization at a temperature below the Curie temperature.
Magnetic hysteresis - phenomenon dependencies vector magnetization and vector magnetic fields in matter not only from attached external fields, but and from background this sample
A magnetic field - power field , acting on moving electric charges and on bodies with magnetic moment, regardless of the state of their movement;magnetic component of the electromagnetic fields .
The magnetic field lines are imaginary lines, the tangents to which at each point of the field coincide in direction with the magnetic induction vector.
For a magnetic field, the principle of superposition is valid: at each point in space, the vector of magnetic induction B∑ → B∑→created at this point by all sources of magnetic fields is equal to the vector sum of the magnetic induction vectors bk→ Bk→created at this point by all sources of magnetic fields:
28. Law of Biot-Savart-Laplace. Full current law.
The formulation of Biot Savart Laplace's law is as follows: When a direct current passes through a closed circuit in vacuum, for a point at a distance r0 from the circuit, the magnetic induction will have the form.
where I current in the circuit
gamma contour along which the integration is carried out
r0 arbitrary point
Full current law this is the law relating the circulation of the magnetic field strength vector and the current.
The circulation of the magnetic field strength vector along the circuit is equal to the algebraic sum of the currents covered by this circuit.
29. Magnetic field of a conductor with current. Magnetic moment of circular current.
30. The action of a magnetic field on a conductor with current. Ampere's law. Interaction of currents .
F = B I l sinα ,
where α - the angle between the vectors of magnetic induction and current,B - magnetic field induction,I - current in the conductor,l - conductor length.
Interaction of currents. If two wires are included in the DC circuit, then: Closely spaced parallel conductors connected in series repel each other. Conductors connected in parallel attract each other.
31. Action of electric and magnetic fields on a moving charge. Lorentz force.
Lorentz force - strength, with which electromagnetic field according to the classical (non-quantum) electrodynamics acts on point charged particle. Sometimes the Lorentz force is called the force acting on a moving with a speed charge only from the side magnetic field, often the full force - from the electromagnetic field in general , in other words, from the side electric and magnetic fields.
32. The action of a magnetic field on matter. Dia-, para- and ferromagnets. Magnetic hysteresis.
B= B 0 + B 1
where B⃗ B → - magnetic field induction in matter; B⃗ 0 B→0 - magnetic field induction in vacuum, B⃗ 1 B→1 - magnetic induction of the field that arose due to the magnetization of the substance.
Substances for which the magnetic permeability is slightly less than unity (μ< 1), называются diamagnets, slightly greater than one (μ > 1) - paramagnets.
ferromagnet - the substance or material in which the phenomenon is observed ferromagnetism, i.e., the appearance of spontaneous magnetization at a temperature below the Curie temperature.
Magnetic hysteresis - phenomenon dependencies vector magnetization and vector magnetic fields in matter not only from attached external fields, but and from background this sample
Without a doubt, lines of force magnetic field is now known to everyone. At least, even at school, their manifestation is demonstrated in physics lessons. Remember how the teacher placed a permanent magnet (or even two, combining the orientation of their poles) under a sheet of paper, and on top of it he poured metal filings taken in the labor training room? It is quite clear that the metal had to be held on the sheet, but something strange was observed - lines were clearly traced along which sawdust lined up. Notice - not evenly, but in stripes. These are the magnetic field lines. Or rather, their manifestation. What happened then and how can it be explained?
Let's start from afar. Together with us in the visible physical world coexists a special kind of matter - a magnetic field. It provides interaction between moving elementary particles or larger bodies with electric charge or natural Electrical and are not only interconnected with each other, but often generate themselves. For example, a wire carrying electricity creates a magnetic field around itself. The reverse is also true: the action of alternating magnetic fields on a closed conducting circuit creates a movement of charge carriers in it. The latter property is used in generators that supply electrical energy to all consumers. A striking example of electromagnetic fields is light.
The lines of force of the magnetic field around the conductor rotate or, which is also true, are characterized by a directed vector of magnetic induction. The direction of rotation is determined by the gimlet rule. The indicated lines are a convention, since the field spreads evenly in all directions. The thing is that it can be represented as an infinite number of lines, some of which have a more pronounced tension. That is why some “lines” are clearly traced in and sawdust. Interestingly, the lines of force of the magnetic field are never interrupted, so it is impossible to say unequivocally where the beginning is and where the end is.
When permanent magnet(or an electromagnet similar to it), there are always two poles, which have received the code names North and South. The lines mentioned in this case are rings and ovals connecting both poles. Sometimes this is described in terms of interacting monopoles, but then a contradiction arises, according to which the monopoles cannot be separated. That is, any attempt to divide the magnet will result in several bipolar parts.
Of great interest are the properties of lines of force. We have already talked about continuity, but the ability to create an electric current in a conductor is of practical interest. The meaning of this is as follows: if the conducting circuit is crossed by lines (or the conductor itself is moving in a magnetic field), then additional energy is imparted to the electrons in the outer orbits of the atoms of the material, allowing them to begin independent directed movement. It can be said that the magnetic field seems to “knock out” charged particles from the crystal lattice. This phenomenon has been named electromagnetic induction and is currently the main way to obtain primary electrical energy. It was discovered experimentally in 1831 by the English physicist Michael Faraday.
The study of magnetic fields began as early as 1269, when P. Peregrine discovered the interaction of a spherical magnet with steel needles. Almost 300 years later, W. G. Colchester suggested that he himself was a huge magnet with two poles. Further magnetic phenomena studied by such famous scientists as Lorentz, Maxwell, Ampère, Einstein, etc.
