A report on Magnetic field

The shape of the magnetic field produced by a horseshoe magnet is revealed by the orientation of iron filings sprinkled on a piece of paper above the magnet.
Right hand grip rule: a current flowing in the direction of the white arrow produces a magnetic field shown by the red arrows.
A Solenoid with electric current running through it behaves like a magnet.
A sketch of Earth's magnetic field representing the source of the field as a magnet. The south pole of the magnetic field is near the geographic north pole of the Earth.
One of the first drawings of a magnetic field, by René Descartes, 1644, showing the Earth attracting lodestones. It illustrated his theory that magnetism was caused by the circulation of tiny helical particles, "threaded parts", through threaded pores in magnets.
Hans Christian Ørsted, Der Geist in der Natur, 1854

Vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials.

- Magnetic field
The shape of the magnetic field produced by a horseshoe magnet is revealed by the orientation of iron filings sprinkled on a piece of paper above the magnet.

101 related topics with Alpha

Overall

Electron micrograph of a Ni nanocrystal inside a single wall carbon nanotube; scale bar 5 nm.

Nickel

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Chemical element with symbol Ni and atomic number 28.

Chemical element with symbol Ni and atomic number 28.

Electron micrograph of a Ni nanocrystal inside a single wall carbon nanotube; scale bar 5 nm.
Widmanstätten pattern showing the two forms of nickel-iron, kamacite and taenite, in an octahedrite meteorite
Tetracarbonyl nickel
Structure of ion
Color of various Ni(II) complexes in aqueous solution. From left to right,, [Ni(C2H4(NH2)2)]2+, ,
Crystals of hydrated nickel(II) sulfate.
Nickel(III) antimonide
Nickeline/niccolite
Dutch coins made of pure nickel
Time trend of nickel production
Nickel ores grade evolution in some leading nickel producing countries.
Evolution of the annual nickel extraction, according to ores.
Electrolytically refined nickel nodule, with green, crystallized nickel-electrolyte salts visible in the pores.
Highly purified nickel spheres made by the Mond process.
Nickel foam (top) and its internal structure (bottom)
A "horseshoe magnet" made of alnico nickel alloy.

Nickel is naturally magnetostrictive: in the presence of a magnetic field, the material undergoes a small change in length.

Three-phase totally-enclosed fan-cooled (TEFC) induction motor with end cover on the left, and without end cover to show cooling fan on the right. In TEFC motors, interior heat losses are dissipated indirectly through enclosure fins, mostly by forced air convection.

Induction motor

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Three-phase totally-enclosed fan-cooled (TEFC) induction motor with end cover on the left, and without end cover to show cooling fan on the right. In TEFC motors, interior heat losses are dissipated indirectly through enclosure fins, mostly by forced air convection.
Cutaway view through stator of TEFC induction motor, showing rotor with internal air circulation vanes. Many such motors have a symmetric armature, and the frame may be reversed to place the electrical connection box (not shown) on the opposite side.
A model of Nikola Tesla's first induction motor at the Tesla Museum in Belgrade, Serbia
Squirrel-cage rotor construction, showing only the center three laminations
A three-phase power supply provides a rotating magnetic field in an induction motor
Inherent slip - unequal rotation frequency of stator field and the rotor
Typical torque curve as a function of slip, represented as "g" here
Speed-torque curves for four induction motor types: A) Single-phase, B) Polyphase cage, C) Polyphase cage deep bar, D) Polyphase double cage
Typical speed-torque curve for NEMA Design B Motor
Magnetic flux in shaded pole motor.
Typical speed-torque curves for different motor input frequencies as for example used with variable-frequency drives
Typical winding pattern for a three-phase (U, W, V), four-pole motor. Note the interleaving of the pole windings and the resulting quadrupole field.

An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding.

Ferrimagnetic ordering

Ferrimagnetism

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Material that has populations of atoms with opposing magnetic moments, as in antiferromagnetism.

Material that has populations of atoms with opposing magnetic moments, as in antiferromagnetism.

Ferrimagnetic ordering
➀ Below the magnetization compensation point, ferrimagnetic material is magnetic. ➁ At the compensation point, the magnetic components cancel each other and the total magnetic moment is zero. ➂ Above the Curie temperature, the material loses magnetism.

against magnetic field

Miniature synchronous motor used in analog clocks. The rotor is made of permanent magnet.

Synchronous motor

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AC electric motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles.

AC electric motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles.

Miniature synchronous motor used in analog clocks. The rotor is made of permanent magnet.
Small synchronous motor with integral stepdown gear from a microwave oven
Single-phase 60 Hz 1800 RPM synchronous motor for Teletype machine, non-excited rotor type, manufactured from 1930 to 1955
DC-excited motor, 1917. The exciter is clearly seen at the rear of the machine.
Rotor of a large water pump. The slip rings can be seen below the rotor drum.
Stator winding of a large water pump
The rotating magnetic field is formed from the sum of the magnetic field vectors of the three phases of the stator windings.
V-curve of a synchronous machine

Synchronous motors contain multiphase AC electromagnets on the stator of the motor that create a magnetic field which rotates in time with the oscillations of the line current.

Illustration of the dynamo mechanism that creates the Earth's magnetic field: convection currents of fluid metal in the Earth's outer core, driven by heat flow from the inner core, organized into rolls by the Coriolis force, create circulating electric currents, which generate the magnetic field.

Dynamo theory

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Illustration of the dynamo mechanism that creates the Earth's magnetic field: convection currents of fluid metal in the Earth's outer core, driven by heat flow from the inner core, organized into rolls by the Coriolis force, create circulating electric currents, which generate the magnetic field.
A visual representation of the Glatzmaier model before dipole reversal
A visual representation of the Glatzmaier model during dipole reversal
A visual representation of the Glatzmaier model after dipole reversal

In physics, the dynamo theory proposes a mechanism by which a celestial body such as Earth or a star generates a magnetic field.

Search coil magnetometer

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Inductive sensor , is a magnetometer which measures the varying magnetic flux.

Inductive sensor , is a magnetometer which measures the varying magnetic flux.

A more crude search coil also called exploring coil is also used in laboratory experiments in schools to measure the magnetic field in a certain region of space.

A modern military compass, with included sight device for aligning

Compass

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Device that shows the cardinal directions used for navigation and geographic orientation.

Device that shows the cardinal directions used for navigation and geographic orientation.

A modern military compass, with included sight device for aligning
A military compass that was used during World War I
Figurine of a man holding a compass, Song dynasty
A liquid-filled protractor or orienteering compass with lanyard
Cammenga air filled lensatic compass
Thumb compass on left
3-axis electronic magnetometer AKM8975 by AKM Semiconductor
A standard Brunton Geo, used commonly by geologists
A close up photo of a geological compass
Wrist compass of the Soviet Army with counterclockwise double graduation: 60° (like a watch) and 360°
A binnacle containing a ship's standard compass, with the two iron balls which correct the effects of ferromagnetic materials. This unit is on display in a museum.
Turning the compass scale on the map (D – the local magnetic declination)
When the needle is aligned with and superimposed over the outlined orienting arrow on the bottom of the capsule, the degree figure on the compass ring at the direction-of-travel (DOT) indicator gives the magnetic bearing to the target (mountain).
Soldier using a prismatic compass to get an azimuth

The magnetic field exerts a torque on the needle, pulling the North end or pole of the needle approximately toward the Earth's North magnetic pole, and pulling the other toward the Earth's South magnetic pole.

Albert Einstein around 1905, the year his "Annus Mirabilis papers" were published. These included Zur Elektrodynamik bewegter Körper, the paper founding special relativity.

Special relativity

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1) The laws of physics are invariant (that is, identical) in all inertial frames of reference (that is, frames of reference with no acceleration).

1) The laws of physics are invariant (that is, identical) in all inertial frames of reference (that is, frames of reference with no acceleration).

Albert Einstein around 1905, the year his "Annus Mirabilis papers" were published. These included Zur Elektrodynamik bewegter Körper, the paper founding special relativity.
Figure 2–1. The primed system is in motion relative to the unprimed system with constant velocity v only along the x-axis, from the perspective of an observer stationary in the unprimed system. By the principle of relativity, an observer stationary in the primed system will view a likewise construction except that the velocity they record will be −v. The changing of the speed of propagation of interaction from infinite in non-relativistic mechanics to a finite value will require a modification of the transformation equations mapping events in one frame to another.
Figure 4–1. The three events (A, B, C) are simultaneous in the reference frame of some observer O. In a reference frame moving at v = 0.3c, as measured by O, the events occur in the order C, B, A. In a reference frame moving at v = −0.5c with respect to O, the events occur in the order A, B, C. The white lines, the lines of simultaneity, move from the past to the future in the respective frames (green coordinate axes), highlighting events residing on them. They are the locus of all events occurring at the same time in the respective frame. The gray area is the light cone with respect to the origin of all considered frames.
Figure 4–3. Light cone
Figure 5–1. Highly simplified diagram of Fizeau's 1851 experiment.
Figure 5–2. Illustration of stellar aberration
Figure 5–3. Transverse Doppler effect for two scenarios: (a) receiver moving in a circle around the source; (b) source moving in a circle around the receiver.
Figure 5–4. Comparison of the measured length contraction of a cube versus its visual appearance.
Figure 5-5. Galaxy M87 streams out a black-hole-powered jet of electrons and other sub-atomic particles traveling at nearly the speed of light.
Figure 10–1. Orthogonality and rotation of coordinate systems compared between left: Euclidean space through circular angle φ, right: in Minkowski spacetime through hyperbolic angle φ (red lines labelled c denote the worldlines of a light signal, a vector is orthogonal to itself if it lies on this line).
Figure 10–2. Three-dimensional dual-cone.

The Lorentz transformation of the electric field of a moving charge into a non-moving observer's reference frame results in the appearance of a mathematical term commonly called the magnetic field.

Momentum of a pool cue ball is transferred to the racked balls after collision.

Momentum

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Product of the mass and velocity of an object.

Product of the mass and velocity of an object.

Momentum of a pool cue ball is transferred to the racked balls after collision.
Elastic collision of equal masses
Elastic collision of unequal masses
a perfectly inelastic collision between equal masses
Two-dimensional elastic collision. There is no motion perpendicular to the image, so only two components are needed to represent the velocities and momenta. The two blue vectors represent velocities after the collision and add vectorially to get the initial (red) velocity.
Motion of a material body

and magnetic field

Finding the direction of the cross product by the right-hand rule

Right-hand rule

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Common mnemonic for understanding orientation of axes in three-dimensional space.

Common mnemonic for understanding orientation of axes in three-dimensional space.

Finding the direction of the cross product by the right-hand rule
Conventional direction of the axis of a rotating body
Left-handed coordinates on the left, right-handed coordinates on the right.
Left- and right-handed screws
Prediction of direction of field (B), given that the current I flows in the direction of the thumb
Finding direction of magnetic field (B) for an electrical coil
Illustration of the right-hand rule on the ninth series of the Swiss 200-francs banknote.

It reveals a connection between the current and the magnetic field lines in the magnetic field that the current created.