Magnetic flux formula through tension. Magnetic Flux – Knowledge Hypermarket

The flow of the magnetic induction vector B through any surface. Magnetic flux through small area dS, within which vector B is unchanged, is equal to dФ = ВndS, where Bn is the projection of the vector onto the normal to the area dS. Magnetic flux F through the final... ... Big encyclopedic Dictionary

MAGNETIC FLUX- (magnetic induction flux), flux F of the magnetic vector. induction B through k.l. surface. M. p. dФ through a small area dS, within the limits of which the vector B can be considered unchanged, is expressed by the product of the area size and the projection Bn of the vector onto ... ... Physical encyclopedia

magnetic flux- A scalar quantity equal to the flux of magnetic induction. [GOST R 52002 2003] magnetic flux The flux of magnetic induction through a surface perpendicular to the magnetic field, defined as the product of the magnetic induction at a given point by the area... ... Technical Translator's Guide

MAGNETIC FLUX- (symbol F), a measure of the strength and extent of the MAGNETIC FIELD. The flux through area A at right angles to the same magnetic field is Ф = mHA, where m is the magnetic PERMEABILITY of the medium, and H is the intensity magnetic field. Magnetic flux density is the flux... ... Scientific and technical encyclopedic dictionary

MAGNETIC FLUX- flux Ф of the magnetic induction vector (see (5)) B through the surface S normal to the vector B in a uniform magnetic field. SI unit of magnetic flux (cm) ... Big Polytechnic Encyclopedia

MAGNETIC FLUX- a value characterizing the magnetic effect on a given surface. The magnetic field is measured by the number of magnetic lines of force passing through a given surface. Technical railway dictionary. M.: State transport... ... Technical railway dictionary

Magnetic flux- a scalar quantity equal to the flux of magnetic induction... Source: ELECTRICAL ENGINEERING. TERMS AND DEFINITIONS OF BASIC CONCEPTS. GOST R 52002 2003 (approved by Resolution of the State Standard of the Russian Federation dated 01/09/2003 N 3 art.) ... Official terminology

magnetic flux- flux of magnetic induction vector B through any surface. The magnetic flux through a small area dS, within which the vector B is unchanged, is equal to dФ = BndS, where Bn is the projection of the vector onto the normal to the area dS. Magnetic flux F through the final... ... encyclopedic Dictionary

magnetic flux- , the flux of magnetic induction is the flux of the magnetic induction vector through any surface. For a closed surface, the total magnetic flux equal to zero, which reflects the solenoidal nature of the magnetic field, i.e. the absence in nature ... Encyclopedic Dictionary of Metallurgy

Magnetic flux- 12. Magnetic flux Magnetic induction flux Source: GOST 19880 74: Electrical engineering. Basic concepts. Terms and definitions original document 12 magnetic on ... Dictionary-reference book of terms of normative and technical documentation

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, Mitkevich V.F.. This book contains a lot that is not always paid due attention when we're talking about about magnetic flux, and what has not yet been sufficiently clearly stated or was not... Buy for 2252 UAH (Ukraine only)
Magnetic flux and its transformation, Mitkevich V.F.. This book will be produced in accordance with your order using Print-on-Demand technology.

This book contains a lot that is not always given due attention when it comes to... The flow of the magnetic induction vector B through any surface. The magnetic flux through a small area dS, within which the vector B is unchanged, is equal to dФ = ВndS, where Bn is the projection of the vector onto the normal to the area dS. Magnetic flux F through the final... ...

MAGNETIC FLUX Big Encyclopedic Dictionary Scientific and technical encyclopedic dictionary

magnetic flux- (symbol F), a measure of the strength and extent of the MAGNETIC FIELD. The flux through area A at right angles to the same magnetic field is Ф = mHA, where m is the magnetic PERMEABILITY of the medium, and H is the intensity of the magnetic field. Magnetic flux density is the flux... ... Encyclopedic Dictionary of Metallurgy

Books

- , the flux of magnetic induction is the flux of the magnetic induction vector through any surface. For a closed surface, the total magnetic flux is zero, which reflects the solenoidal nature of the magnetic field, i.e. the absence in nature...
Magnetic flux and its transformation, Mitkevich V.F.. This book will be produced in accordance with your order using Print-on-Demand technology.

, Mitkevich V. F.. This book contains a lot that is not always paid due attention when it comes to magnetic flux, and that has not yet been stated clearly enough or has not been... Buy for 2252 UAH (Ukraine only) Among physical quantities important place

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Magnetic flux formula

What is magnetic flux

This is a quantity that determines the level of the magnetic field passing through the surface. It is designated “FF” and depends on the strength of the field and the angle of passage of the field through this surface.

It is calculated according to the formula:

FF=B⋅S⋅cosα, where:
FF – magnetic flux;
B is the magnitude of magnetic induction;
cosα is the cosine of the angle between the perpendicular to the surface and the flow.

The SI unit of measurement is “weber” (Wb). 1 Weber is created by a field of 1 Tesla passing perpendicular to a surface with an area of 1 m².

Thus, the flow is maximum when its direction coincides with the vertical and is equal to “0” if it is parallel to the surface.

Interesting. The magnetic flux formula is similar to the formula by which illumination is calculated.

Permanent magnets

One of the field sources is permanent magnets. They have been known for many centuries. The compass needle was made from magnetized iron, and in Ancient Greece There was a legend about an island that attracts metal parts of ships.

There are permanent magnets various shapes and are made from different materials:

iron ones are the cheapest, but have less attractive force;
neodymium - made from an alloy of neodymium, iron and boron;
Alnico is an alloy of iron, aluminum, nickel and cobalt.

All magnets are bipolar. This is most noticeable in rod and horseshoe devices.

If the rod is hung by the middle or placed on a floating piece of wood or foam, it will turn in the north-south direction. The pole pointing north is called the north pole and is painted in color on laboratory instruments. Blue colour and denoted by "N". The opposite one, pointing south, is red and labeled "S". Magnets with like poles attract, and with opposite poles they repel.

In 1851, Michael Faraday proposed the concept of closed induction lines. These lines come out of the north pole of the magnet, pass through the surrounding space, enter the south and return to the north inside the device. The lines and field strength are closest at the poles. The attractive force is also higher here.

If you put a piece of glass on the device and sprinkle iron filings on top in a thin layer, they will be located along the magnetic field lines. When several devices are placed nearby, the sawdust will show the interaction between them: attraction or repulsion.

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Magnet and iron filings

Earth's magnetic field

Our planet can be imagined as a magnet, the axis of which is inclined by 12 degrees. The intersections of this axis with the surface are called magnetic poles. Like any magnet, power lines The lands go from the north pole to the south. Near the poles they run perpendicular to the surface, so there the compass needle is unreliable, and other methods have to be used.

Particles of the “solar wind” have an electric charge, so when moving around them, a magnetic field appears, interacting with the Earth’s field and directing these particles along the lines of force. Thus, this field protects earth's surface from cosmic radiation. However, near the poles these lines are directed perpendicular to the surface, and charged particles enter the atmosphere, causing the northern lights.

Electromagnets

In 1820, Hans Oersted, while conducting experiments, saw the effect of a conductor through which an electric current flows on a compass needle. A few days later, Andre-Marie Ampere discovered the mutual attraction of two wires through which a current flowed in the same direction.

Interesting. During electric welding, nearby cables move when the current changes.

Ampere later suggested that this was due to the magnetic induction of current flowing through the wires.

In a coil wound with an insulated wire through which electric current flows, the fields of the individual conductors reinforce each other. To increase the attractive force, the coil is wound on an open steel core. This core is magnetized and attracts iron parts or the other half of the core in relays and contactors.

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Electromagnets

Electromagnetic induction

When the magnetic flux changes, an electric current is induced in the wire. This fact does not depend on what reasons this change was caused: displacement permanent magnet, movement of the wire or change in current strength in a nearby conductor.

This phenomenon was discovered by Michael Faraday on August 29, 1831. His experiments showed that the EMF (electromotive force) appearing in a circuit bounded by conductors is directly proportional to the rate of change of flux passing through the area of this circuit.

Important! For an emf to occur, the wire must cross the power lines. When moving along the lines, there is no EMF.

If the coil in which the emf occurs is switched on electrical circuit, then a current arises in the winding, creating its own electromagnetic field in the inductor.

Right hand rule

When a conductor moves in a magnetic field, an emf is induced in it. Its direction depends on the direction of movement of the wire. The method by which the direction of magnetic induction is determined is called the “method right hand».

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Right hand rule

Calculation of the magnitude of the magnetic field is important for design electric machines and transformers.

Video

Right hand or gimlet rule:

The direction of the magnetic field lines and the direction of the current creating it are interconnected by the well-known rule of the right hand or gimlet, which was introduced by D. Maxwell and is illustrated by the following drawings:

Few people know that a gimlet is a tool for drilling holes in wood. Therefore, it is more understandable to call this rule the rule of a screw, screw or corkscrew. However, grabbing the wire as in the picture is sometimes life-threatening!

Magnetic induction B:

Magnetic induction- is the main fundamental characteristic of the magnetic field, similar to the electric field strength vector E. The magnetic induction vector is always directed tangentially to the magnetic line and shows its direction and strength. The unit of magnetic induction in B = 1 T is taken to be the magnetic induction of a uniform field, in which a section of conductor with a length of l= 1 m, with a current strength in it in I= 1 A, acts from the side of the field maximum force Ampere - F= 1 H. The direction of the Ampere force is determined by the left-hand rule. In the CGS system, magnetic field induction is measured in gauss (G), in the SI system - in tesla (T).

Magnetic field strength H:

Another characteristic of the magnetic field is tension, which is an analogue of the electric displacement vector D in electrostatics. Determined by the formula:

Magnetic field strength is a vector quantity, is a quantitative characteristic of the magnetic field and does not depend on magnetic properties environment. In the CGS system, magnetic field strength is measured in oersteds (Oe), in the SI system - in amperes per meter (A/m).

Magnetic flux F:

Magnetic flux F - scalar physical quantity, characterizing the number of magnetic induction lines penetrating a closed circuit. Let's consider special case. IN uniform magnetic field, the magnitude of the induction vector of which is equal to ∣B ∣, is placed flat closed loop area S. The normal n to the contour plane makes an angle α with the direction of the magnetic induction vector B. The magnetic flux through the surface is the quantity Ф, determined by the relation:

In general, magnetic flux is defined as the integral of the magnetic induction vector B through a finite surface S.

It is worth noting that the magnetic flux through any closed surface is zero (Gauss's theorem for magnetic fields). This means that the magnetic field lines do not break off anywhere, i.e. the magnetic field has a vortex nature, and also that it is impossible for the existence of magnetic charges that would create a magnetic field in the same way that electric charges create an electric field. In the SI, the unit of magnetic flux is Weber (Wb), in the CGS system it is Maxwell (Mx); 1 Wb = 10 8 μs.

Definition of inductance:

Inductance is a coefficient of proportionality between the electric current flowing in any closed circuit and the magnetic flux created by this current through the surface of which this circuit is the edge.

Otherwise, inductance is a proportionality coefficient in the self-induction formula.

In SI units, inductance is measured in henry (H). A circuit has an inductance of one henry if, when the current changes by one ampere per second, a Self-induced emf one volt.

The term "inductance" was proposed by Oliver Heaviside, a self-taught English scientist in 1886. Simply put, inductance is the property of a current-carrying conductor to accumulate energy in a magnetic field, equivalent to capacitance for an electric field. It does not depend on the magnitude of the current, but only on the shape and size of the conductor carrying the current. To increase the inductance, the conductor is wound in coils, the calculation of which is what the program is dedicated to

Electric dipole moment
Electric charge
Electrical induction
Electric field
Electrostatic potential

Magnetostatics
Biot-Savart-Laplace law Ampere's law Magnetic moment A magnetic field Magnetic flux Magnetic induction

Electrodynamics
Vector potential Dipole Lienard-Wiechert potentials Lorentz force Bias current Unipolar induction Maxwell's equations Electricity Electromotive force Electromagnetic induction Electromagnetic radiation Electromagnetic field

Electrical circuit
Ohm's law Kirchhoff's laws Inductance Radio waveguide Resonator Electrical capacity Electrical conductivity Electrical resistance Electrical impedance

Famous scientists
Henry Cavendish Michael Faraday Nikola Tesla Andre-Marie Ampère Gustav Robert Kirchhoff James Clerk (Clark) Maxwell Henry Rudolf Hertz Albert Abraham Michelson Robert Andrews Milliken

Magnetic flux quantization

Values of magnetic flux Φ passing through

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Excerpt characterizing Magnetic Flux

“C"est bien, mais ne demenagez pas de chez le prince Vasile. Il est bon d"avoir un ami comme le prince,” she said, smiling at Prince Vasily. - J"en sais quelque chose. N"est ce pas? [That's good, but don't move away from Prince Vasily. It's good to have such a friend. I know something about this. Isn't that right?] And you are still so young. You need advice. Don't be angry with me for taking advantage of old women's rights. “She fell silent, as women always remain silent, expecting something after they say about their years. – If you get married, then it’s a different matter. – And she combined them into one look. Pierre did not look at Helen, and she did not look at him. But she was still terribly close to him. He mumbled something and blushed.
Returning home, Pierre could not fall asleep for a long time, thinking about what happened to him. What happened to him? Nothing. He just realized that the woman he knew as a child, about whom he absentmindedly said: “Yes, she’s good,” when they told him that Helen was beautiful, he realized that this woman could belong to him.
“But she’s stupid, I said myself that she’s stupid,” he thought. “There is something nasty in the feeling that she aroused in me, something forbidden.” They told me that her brother Anatole was in love with her, and she was in love with him, that there was a whole story, and that Anatole was sent away from this. Her brother is Hippolytus... Her father is Prince Vasily... This is not good,” he thought; and at the same time as he reasoned like this (these reasonings still remained unfinished), he found himself smiling and realized that another series of reasoning was emerging from behind the first, that at the same time he was thinking about her insignificance and dreaming about how she will be his wife, how she can love him, how she can be completely different, and how everything that he thought and heard about her may not be true. And again he saw her not as some daughter of Prince Vasily, but saw her whole body, only covered with a gray dress. “But no, why didn’t this thought occur to me before?” And again he told himself that this was impossible; that something disgusting, unnatural, as it seemed to him, would be dishonest in this marriage. He remembered her previous words, looks, and the words and looks of those who saw them together. He remembered the words and looks of Anna Pavlovna when she told him about the house, he remembered thousands of such hints from Prince Vasily and others, and horror came over him, whether he had already tied himself in some way in carrying out such a task, which was obviously not good and which he should not do. But at the same time, as he expressed this decision to himself, from the other side of his soul her image emerged with all its feminine beauty.

In November 1805, Prince Vasily was supposed to go to an audit in four provinces. He arranged this appointment for himself in order to visit his ruined estates at the same time, and taking with him (at the location of his regiment) his son Anatoly, he and he would go to Prince Nikolai Andreevich Bolkonsky in order to marry his son to the daughter of this rich man old man. But before leaving and these new affairs, Prince Vasily needed to resolve matters with Pierre, who, however, Lately spent whole days at home, that is, with Prince Vasily, with whom he lived, he was funny, excited and stupid (as a lover should be) in the presence of Helen, but still did not propose.