This measurement is basically just what happens when you put the particle into a magnetic field and watch how it twists to align itself in the same way a bar magnet aligns itself when you put it near another bar magnet.
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Instead it uses permanent room-temperature magnets, similar to the familiar bar magnet, only more powerful.
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Saturn, too, has a field like a bar magnet, though its field aligns with its rotational axis.
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Think of the Earth's magnetic field as shaped by a bar magnet at the centre of the planet.
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Take any old bar magnet and cut it in half and it will still have a North and a South pole.
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Rotating columns of metal in Earth's outer core give it a magnetic field that looks like that of a tilted bar magnet.
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From these two poles, bunched up magnetic field lines — invisible tendrils that represent the direction and strength of this planetary bar magnet — reach out into space as the planet travels on its orbit.
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Since a bar magnet gets its ferromagnetism from electrons distributed evenly throughout the bar, when a bar magnet is cut in half, each of the resulting pieces is a smaller bar magnet. Even though a magnet is said to have a north pole and a south pole, these two poles cannot be separated from each other. A monopole—if such a thing exists—would be a new and fundamentally different kind of magnetic object. It would act as an isolated north pole, not attached to a south pole, or vice versa.
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The second reason is that the pole pieces can make tuning and placement of the strings much more difficult. Using the bar magnet however gave the strings a more balanced output. The design of the bar magnet gives it a smoother distortion, better sustain through the amplifier, and have less fade onto the strings than the design of pole pieces.
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It is impossible to make magnetic monopoles from a bar magnet. If a bar magnet is cut in half, it is not the case that one half has the north pole and the other half has the south pole. Instead, each piece has its own north and south poles. A magnetic monopole cannot be created from normal matter such as atoms and electrons, but would instead be a new elementary particle.
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This aspect of electromagnetic induction is the operating principle behind many electric generators: for example, a rotating bar magnet creates a changing magnetic field, which in turn generates an electric field in a nearby wire.
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If the bit was beside an unmagnetized bar magnet in the card, the field was not opposed and the flip caused a current pulse in the twistor wire, reading a "1". However, by magnetizing the bar at that bit, the bar magnet opposed the field being created by the solenoid current, causing it to be below the write strength, and preventing the flip. This read a "0". The permanent magnet twistor (PMT) was re-programmed by removing the plates and placing them over a custom writer.
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This induction was due to the change in magnetic flux that occurred when the battery was connected and disconnected. Within two months, Faraday had found several other manifestations of electromagnetic induction. For example, he saw transient currents when he quickly slid a bar magnet in and out of a coil of wires, and he generated a steady (DC) current by rotating a copper disk near the bar magnet with a sliding electrical lead ("Faraday's disk"). Faraday's disk, the first left Michael Faraday explained electromagnetic induction using a concept he called lines of force.
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The "Magna II" pickups were overwound, with full magnet loading in both coils. One outside bar magnet loaded coil and a 6 internal pole piece magnet loaded coil. The MV2 Velvet Brick neck pickup was designed by Bill Lawrence. The Velvet Brick pickups were later mass-produced.
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Field of a cylindrical bar magnet computed accurately Two different models exist for magnets: magnetic poles and atomic currents. Although for many purposes it is convenient to think of a magnet as having distinct north and south magnetic poles, the concept of poles should not be taken literally: it is merely a way of referring to the two different ends of a magnet. The magnet does not have distinct north or south particles on opposing sides. If a bar magnet is broken into two pieces, in an attempt to separate the north and south poles, the result will be two bar magnets, each of which has both a north and south pole.
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The inner cylinder is shorter, leaving an empty space at the bottom.Path, p. 5 An electromagnet inside the inner cylinder sets up an initial field. The field is similar to that of a bar magnet, running vertically down the center of the inner cylinder and up the outside of the apparatus.
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A special type of zero- center ammeter for testing high currents in cars and trucks has a pivoted bar magnet that moves the pointer, and a fixed bar magnet to keep the pointer centered with no current. The magnetic field around the wire carrying current to be measured deflects the moving magnet. Since the ammeter shunt has a very low resistance, mistakenly wiring the ammeter in parallel with a voltage source will cause a short circuit, at best blowing a fuse, possibly damaging the instrument and wiring, and exposing an observer to injury. In AC circuits, a current transformer converts the magnetic field around a conductor into a small AC current, typically either or at full rated current, that can be easily read by a meter.
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275 In 1835, they replaced the batteries of their telegraph with a large magneto-electric apparatus which generated telegraph pulses as the operator moved a coil relative to a bar magnet. This machine was made by Carl August von Steinheil.Fahie, pp. 320–321 The Gauss and Weber telegraph remained in daily service until 1838.
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Exploring the physics and engineering behind this design, requires looking at basic magnetism. A standard bar magnet has two magnetic poles: north and south. (The north will read positive on a gauss meter and the south will read negative.) Magnetic field are mapped using magnetic flux lines. These lines are a graphical representation of the magnetic field density.
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When the Hamiltonian of a system (or the Lagrangian) has a certain symmetry, but the vacuum does not, then one says that spontaneous symmetry breaking (SSB) has taken place. A familiar example of SSB is in ferromagnetic materials. Microscopically, the material consists of atoms with a non-vanishing spin, each of which acts like a tiny bar magnet, i.e., a magnetic dipole.
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The disc served as a combined diaphragm and armature. On speaking into the mouthpiece, the iron diaphragm vibrated with the voice in the magnetic field of the bar-magnet pole, and thereby caused undulatory currents in the coil. These currents, after traveling through the wire to the distant receiver, were received in an identical apparatus. This design was patented by Bell on January 30, 1877.
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Magnetic field lines visualized using iron filings. When a piece of paper is sprinkled with iron filings and placed above a bar magnet, the filings align according to the direction of the magnetic field, forming arcs. Quantum field theory is the result of the combination of classical field theory, quantum mechanics, and special relativity. A brief overview of these theoretical precursors is in order.
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Like the North Magnetic Pole, the North Geomagnetic Pole attracts the north pole of a bar magnet and so is in a physical sense actually a magnetic south pole. It is the center of the region of the magnetosphere in which the Aurora Borealis can be seen. As of 2015 it was located at approximately , over Ellesmere Island, Canada but it is now drifting away from North America and toward Siberia.
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Formally, the field can be expressed as a multipole expansion: A dipole field, plus a quadrupole field, plus an octupole field, etc. At close range, many different fields are possible. For example, for a long, skinny bar magnet with its north pole at one end and south pole at the other, the magnetic field near either end falls off inversely with the square of the distance from that pole.
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The neck itself is made up of five plies of mahogany interspersed with four narrow strips of walnut for added strength. Other features were reverse headstock (with the tuners on the treble side) and "banjo"-style planetary geared tuning keys. The special original Gibson Firebird humbucking pickup(s) – single, dual or triple – were smaller footprint versions of standard Gibson humbucking pickups, but were unique in that inside each of their smaller bobbins contained an AlNiCo bar magnet (standard humbucking pickups AND mini-humbucking pickups have one bar magnet that activates the 6 iron slug poles of one bobbin, and 6 iron screw poles of the other bobbin). Original Firebird pickups were also built without any specific bobbin fasteners – their bobbins (and possible "reflector" plate under the bobbins) were held onto the frame during both the wax potting process (to reduce/eliminate feedback and unwanted noise) and the solid metal cover that was soldered to the frame base.
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The symbol μ has been used in some texts for magnetic permeability and in other texts for magnetic moment. We will use μ for magnetic permeability and m for magnetic moment. For pole strength, we will employ qm. For a bar magnet of cross-section A with uniform magnetization M along its axis, the pole strength is given by qm = MA, so that M can be thought of as a pole strength per unit area.
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Related albedo features continue across the surface to the east and southwest, forming loop-like patterns over the mare. The central feature of Reiner Gamma resembles the dipolar formation created by iron filings on a surface with a bar magnet on the underside. Low- orbiting spacecraft have observed a relatively strong magnetic field associated with each of these albedo markings. Some have speculated that this magnetic field and the patterns were created by cometary impacts.
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It explores the role of sound and musical harmonics in the development and form of crystals, plants and animals. The paper shows how he tested many of his theories in his laboratory. "A New Suspension of the Magnetic Needle" describes a detector he built to measure the Earth's vertical current, and data he gathered using this detector. He also develops his hypothesis that a bar magnet has additional poles, East-West poles.
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Earth's geomagnetic field can be approximated by a tilted dipole (like a bar magnet) placed at the center of Earth. The South Geomagnetic Pole is the point where the axis of this best-fitting tilted dipole intersects Earth's surface in the southern hemisphere. As of 2005 it was calculated to be located at , near the Vostok Station. Because the field is not an exact dipole, the South Geomagnetic Pole does not coincide with the South Magnetic Pole.
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A "horseshoe magnet" made of alnico, an iron alloy. The magnet, made in the shape of a horseshoe, has the two magnetic poles close together. This shape creates a strong magnetic field between the poles, allowing the magnet to pick up a heavy piece of iron. Magnetic field lines of a solenoid electromagnet, which are similar to a bar magnet as illustrated below with the iron filings A magnet is a material or object that produces a magnetic field.
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A movie on the right shows how global declinations have changed over the last few centuries. To analyze global patterns of change in the geomagnetic field, geophysicists fit the field data to a spherical harmonic expansion (see International Geomagnetic Reference Field). The terms in this expansion can be divided into a dipolar part, like the field around a bar magnet, and a nondipolar part. The dipolar part dominates the geomagnetic field and determines the direction of the geomagnetic poles.
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Because CuNiFe pole piece magnets produce less output than a standard humbucker's bar magnet and slugs, the wide range Humbucker requires more winds of wire to produce an output compatible to Standard Humbuckers. The pickup bobbins were wound with approximately 6200 to 6800 turns of 42 awg poly insulated copper wire around the pole-pieces. The Wide Range pickup has a DC resistance of around 10.6 kΩ. These extra winds mean the wide range Humbucker needs a larger casing than standard Humbuckers.
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Comparison of magnetic field (flux density) , demagnetizing field and magnetization inside and outside a cylindrical bar magnet. The red (right) side is the North pole, the green (left) side is the South pole. The demagnetizing field, also called the stray field (outside the magnet), is the magnetic field (H-field)In this article the term 'magnetic field' is used for the magnetic 'H field' while 'magnetic flux density' is used for the magnetic 'B-field'. generated by the magnetization in a magnet.
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A magnet's magnetic moment (also called magnetic dipole moment and usually denoted μ) is a vector that characterizes the magnet's overall magnetic properties. For a bar magnet, the direction of the magnetic moment points from the magnet's south pole to its north pole,Knight, Jones, & Field, "College Physics" (2007) p. 815. and the magnitude relates to how strong and how far apart these poles are. In SI units, the magnetic moment is specified in terms of A·m2 (amperes times meters squared).
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In 1833 Carl Friedrich Gauss and Wilhelm Eduard Weber set up an experimental needle telegraph between their laboratory in the University of Göttingen and the university astronomical observatory about a mile and a half away where they were studying the Earth's magnetic field. The line consisted of a pair of copper wires on posts above rooftop height.Fahie, p. 320 The receiving instrument they used was a converted laboratory instrument, of which the so called needle was a large bar magnet weighing a pound.
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The plastic- coated bar magnet was independently invented in the late 1940s by Edward McLaughlin, of the Torpedo Experimental Establishment (TEE), Greenock, Scotland, who named it the 'flea' because of the way it jumps about if the rotating magnet is driven too fast. The first multi-point magnetic stirrer was developed and patented by Salvador Bonet of SBS Company in 1977. He also introduced the practice of noting the denomination of stirring power in "liters of water", which is a market standard today.
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Comparison of , and inside and outside a cylindrical bar magnet. The force on an electric charge depends on its location, speed and direction; two vector fields are used to describe this force. The first is the electric field, which describes the force acting on a stationary charge and gives the component of the force that is independent of motion. The magnetic field, in contrast, describes the component of the force that is proportional to both the speed and direction of charged particles.
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The equations are non- trivial and also depend on the distance from the magnet and the orientation of the magnet. For simple magnets, points in the direction of a line drawn from the south to the north pole of the magnet. Flipping a bar magnet is equivalent to rotating its by 180 degrees. The magnetic field of larger magnets can be obtained by modeling them as a collection of a large number of small magnets called dipoles each having their own .
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The satellite was initially spin-stabilized, but it was despun after solar paddle erection. About 48 hours later, the satellite's axis of symmetry was oriented with the local magnetic field by means of a strong bar magnet and damping rods. During the first 48 hours of flight, internal temperatures were at the top of the satellite's tolerance. As a result, the two Doppler transmitters (162 MHz and 324 MHz) were kept off during the periods that the spacecraft was 100% illuminated by the sun.
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Red Price released "Week End" as a single in the UK on Pye Records in 1958. With the Comets, Franny Beecher played a black 1956 Gibson Les Paul Custom which was given to him by the Gibson Guitar Company, then based in Kalamazoo, Michigan. Gibson also gave Bill Haley a blonde 1956 Super 400 and a black 1956 Gibson L-7. The Les Paul Custom featured a pair of black single coil P-90 pickups, one of which was a bar magnet P-90.
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The magnetic moment of a magnet is a quantity that determines the torque it will experience in an external magnetic field. A loop of electric current, a bar magnet, an electron, a molecule, and a planet all have magnetic moments. The magnetization or magnetic polarization of a magnetic material is the vector field that expresses the density of permanent or induced magnetic moments. The magnetic moments can originate from microscopic electric currents caused by the motion of electrons in individual atoms, or the spin of the electrons or the nuclei.
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The direction of magnetic field lines represented by iron filings sprinkled on paper placed above a bar magnet. Compass needles point in the direction of the local magnetic field, towards a magnet's south pole and away from its north pole. The field can be visualized by a set of magnetic field lines, that follow the direction of the field at each point. The lines can be constructed by measuring the strength and direction of the magnetic field at a large number of points (or at every point in space).
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In 1833, Carl Friedrich Gauss, head of the Geomagnetic Observatory in Göttingen, published a paper on measurement of the Earth's magnetic field. It described a new instrument that consisted of a permanent bar magnet suspended horizontally from a gold fibre. The difference in the oscillations when the bar was magnetised and when it was demagnetised allowed Gauss to calculate an absolute value for the strength of the Earth's magnetic field. The gauss, the CGS unit of magnetic flux density was named in his honour, defined as one maxwell per square centimeter; it equals 1×10−4 tesla (the SI unit).
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These currents, after traversing the wire, passed through the receiver which consisted of an electromagnet in a tubular metal can having one end partially closed by a thin circular disc of soft iron. When the undulatory current passed through the coil of this electromagnet, the disc vibrated, thereby creating sound waves in the air. This primitive telephone was rapidly improved. The double electromagnet was replaced by a single permanently magnetized bar magnet having a small coil or bobbin of fine wire surrounding one pole, in front of which a thin disc of iron was fixed in a circular mouthpiece.
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Iron filings that have oriented in the magnetic field produced by a bar magnet Detecting magnetic field with compass and with iron filings The magnetic flux density (also called magnetic B field or just magnetic field, usually denoted B) is a vector field. The magnetic B field vector at a given point in space is specified by two properties: # Its direction, which is along the orientation of a compass needle. # Its magnitude (also called strength), which is proportional to how strongly the compass needle orients along that direction. In SI units, the strength of the magnetic B field is given in teslas.
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The field at the surface of the Earth is approximately the same as if a giant bar magnet were positioned at the center of the Earth and tilted at an angle of about 11° off the rotational axis of the Earth (see the figure). The north pole of a magnetic compass needle points roughly north, toward the North Magnetic Pole. However, because a magnetic pole is attracted to its opposite, the North Magnetic Pole is actually the south pole of the geomagnetic field. This confusion in terminology arises because the pole of a magnet is defined by the geographical direction it points.
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As a first-order approximation, Earth's magnetic field can be modeled as a simple dipole (like a bar magnet), tilted about 10° with respect to Earth's rotation axis (which defines the Geographic North and Geographic South Poles) and centered at Earth's center. The North and South Geomagnetic Poles are the antipodal points where the axis of this theoretical dipole intersects Earth's surface. If Earth's magnetic field were a perfect dipole then the field lines would be vertical at the Geomagnetic Poles, and they would coincide with the Magnetic Poles. However, the approximation is imperfect, and so the Magnetic and Geomagnetic Poles lie some distance apart.
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This relocated tailpiece has remained in the Mexican Jazzmaster line ever since. Fender also installed special designed P-90-type high-output single-coil pickups. These P-90 pickups operated with a bar magnet at the base instead of the magnetized polepieces of the original pickups./view_specs.php?full_partno=0141600&name;=Classic+Player+Jazzmaster%26reg%3B+Special September 2010 saw the introduction of the Mexican-made Black Top Jazzmaster HS. This guitar sports a Duncan Designed single-coil Jazzmaster neck pickup and a hot vintage alnico humbucking bridge pickup, with other distinctive touches including skirted black amp knobs, a Jazzmaster tremolo tailpiece (without locking button) and a three-way toggle switch.
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Magnetic field lines can be clearly visualized by sprinkling iron filings over a bar magnet. The modern (post-Einstein) interpretation is that the magnetic field is equivalent to the electric field, but in a different reference frame. Since magnetic fields can be interpreted as electric fields in a different reference frame (and vice versa), special relativity connects the two fields. One postulate of special relativity is length contraction, and because of that, the charge density in the wire increases, so a current-carrying wire viewed in a moving reference frame experiences a length-contracted coulomb force as compared to the wire in a stationary frame.
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Instrumentation for this spacecraft was similar to that of the previous Surveyors and included landing legs, a Vernier propulsion system, and numerous engineering sensors. An alpha-scattering instrument was installed in place of the surface sampler, and a small bar magnet attached to one footpad was included to detect the presence of magnetic material in the lunar soil. The spacecraft landed at 00:46:44 UT on September 11, 1967 (7:46 p.m. EST September 10) in Mare Tranquillitatis, at 1.41° N latitude and 23.18° E longitude (selenographic coordinates), within the rimless edge of a small crater on a slope of about 20 deg.
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The magnetization of a magnetized material is the local value of its magnetic moment per unit volume, usually denoted M, with units A/m. It is a vector field, rather than just a vector (like the magnetic moment), because different areas in a magnet can be magnetized with different directions and strengths (for example, because of domains, see below). A good bar magnet may have a magnetic moment of magnitude 0.1 A•m2 and a volume of 1 cm3, or 1×10−6 m3, and therefore an average magnetization magnitude is 100,000 A/m. Iron can have a magnetization of around a million amperes per meter.
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Magnetic stirrers are often used in chemistry and biology, where they can be used inside hermetically closed vessels or systems, without the need for complicated rotary seals. They are preferred over gear-driven motorized stirrers because they are quieter, more efficient, and have no moving external parts to break or wear out (other than the simple bar magnet itself). Magnetic stir bars work well in glass vessels commonly used for chemical reactions, as glass does not appreciably affect a magnetic field. The limited size of the bar means that magnetic stirrers can only be used for relatively small experiments, of 4 liters or less.
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The Wide Range pickup was conceived to be sonically closer to Fender's single coil pickups than Gibson humbuckers. Fender's single coils use six magnetised pole pieces sitting vertically, while Gibson's humbuckers use a long bar magnet at the pickup's base with six metal slug pole pieces screwed vertically into a base plate. Fender could not, however, simply replace the Humbuckers slugs with screws. Due to the difficulty of machining AlNiCo magnets into screw-type pole pieces, this concept called for the use of the more easily machinable CuNiFe (Copper/Nickel/Iron) rod magnets as pole pieces within the coil structures; functioning more like a regular single coil pickup than a Gibson humbucker.
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There are three reissues of the wide range pickup using two designs: one manufactured in Japan using ceramic magnets and one in Mexico using alnico. Despite an almost identical appearance to the original 1970s unit, both are regular Humbuckers in large cases; surrounded by wax to take up space and prevent resining feedback. The current Mexican reissues, much like a Gibson humbucker, feature a bar magnet underneath the bobbins that abuts to six screw type pole-pieces in each coil; they are simply conventional humbuckers placed in the larger "wide range" humbucker casing, and the gap is filled with wax. Although neither pickup precisely replicates the sound of the original, they are tonally similar.
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It requires energy both to move fluid out of the valleys and up into the spikes, and to increase the surface area of the fluid. In summary, the formation of the corrugations increases the surface free energy and the gravitational energy of the liquid, but reduces the magnetic energy. The corrugations will only form above a critical magnetic field strength, when the reduction in magnetic energy outweighs the increase in surface and gravitation energy terms. Ferrofluid simulations for different parameters of surface tension and magnetic field strengths Ferrofluids have an exceptionally high magnetic susceptibility and the critical magnetic field for the onset of the corrugations can be realised by a small bar magnet.
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Unlike a traditional guitar pickup that uses a plastic or fiber bobbin as a form for winding its coil, the lipstick-tube pickup has its coil wrapped around an alnico VI bar magnet, and then wrapped in tape, usually a cellophane-type tape on vintage units, before being inserted into the metal tube casing. Most vintage Danelectro guitars had their pickups mounted using spring-loaded brackets underneath the tube casing, which could be adjusted for height by means of screws located on the back of the guitar body. Other Danelectro guitars, like the Coral hollowbody series, suspended the pickups from the guitar's top with two screws threaded through the guitar's top and into the brackets. Modern lipstick-tube pickups are usually mounted in a pickguard.
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A small bar magnet attached to the inner sphere aligned that sphere with the earth's magnetic field. As the satellite oscillated about its local vertical because of gravity gradient forces, the outer sphere of the damper rotated about the inner sphere, dissipating the oscillatory energy in the form of heat from the viscous drag of the fluid. This system was more effective than the damping spring-and-weight system used on a previously launched Transit satellite in that it provided equal damping about all three axes of the satellite while the older damper provided no damping about the yaw axis and less damping of the roll axis than for pitch. The new damper also was effective immediately whereas the older technique required several weeks for the spring-mass to compress into operational position.
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The direction of the magnetic moment of any elementary particle is entirely determined by the direction of its spin, with the negative value indicating that any electron's magnetic moment is antiparallel to its spin. The net magnetic moment of any system is a vector sum of contributions from one or both types of sources. For example, the magnetic moment of an atom of hydrogen-1 (the lightest hydrogen isotope, consisting of a proton and an electron) is a vector sum of the following contributions: # the intrinsic moment of the electron, # the orbital motion of the electron around the proton, # the intrinsic moment of the proton. Similarly, the magnetic moment of a bar magnet is the sum of the contributing magnetic moments, which include the intrinsic and orbital magnetic moments of the unpaired electrons of the magnet's material and the nuclear magnetic moments.
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Another model is the Ampère model, where all magnetization is due to the effect of microscopic, or atomic, circular bound currents, also called Ampèrian currents, throughout the material. For a uniformly magnetized cylindrical bar magnet, the net effect of the microscopic bound currents is to make the magnet behave as if there is a macroscopic sheet of electric current flowing around the surface, with local flow direction normal to the cylinder axis. Microscopic currents in atoms inside the material are generally canceled by currents in neighboring atoms, so only the surface makes a net contribution; shaving off the outer layer of a magnet will not destroy its magnetic field, but will leave a new surface of uncancelled currents from the circular currents throughout the material. The right-hand rule tells which direction positively-charged current flows.
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Different sizes of magnetic stir bars A mixture of soil and deionized water is being stirred to calibrate pH The first patent for a magnetic mixer is US 1,242,493, issued 9 October 1917 to Richard H. Stringham of Bountiful, Utah, U.S. Mr. Stringham's mixer used stationary electromagnets in the base, rather than a rotating permanent magnet, to rotate the stirrer. Arthur Rosinger of Newark, New Jersey, U.S. obtained US Patent 2,350,534, titled Magnetic Stirrer on 6 June 1944, having filed an application therefore on 5 October 1942. Mr. Rosinger's patent includes a description of a coated bar magnet placed in a vessel, which is driven by a rotating magnet in a base below the vessel. Mr. Rosinger also explains in his patent that coating the magnet in plastic or covering it with glass or porcelain makes it chemically inert.
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Surveyor 6 was the sixth lunar lander of the American uncrewed Surveyor program that reached the surface of the Moon. Surveyor 6 landed on the Sinus Medii. A total of 30,027 images were transmitted to Earth. This spacecraft was the fourth of the Surveyor series to successfully achieve a soft landing on the Moon, obtain post landing television pictures, determine the abundance of the chemical elements in the lunar soil, obtain touchdown dynamics data, obtain thermal and radar reflectivity data, and conduct a Vernier engine erosion experiment. Virtually identical to Surveyor 5, this spacecraft carried a television camera, a small bar magnet attached to one footpad, and an alpha- scattering instrument as well as the necessary engineering equipment. It landed on November 10, 1967, in Sinus Medii, 0.49 deg in latitude and 1.40 deg w longitude (selenographic coordinates)–the center of the Moon's visible hemisphere.
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A cross- sectional view of the Van Allen radiation belts, noting the point where the South Atlantic Anomaly occurs The Van Allen radiation belts are symmetrical about the Earth's magnetic axis, which is tilted with respect to the Earth's rotational axis by an angle of approximately 11°. The intersection between the magnetic and rotation axes of the Earth is located not at the Earth's center, but some away. Because of this asymmetry, the inner Van Allen belt is closest to the Earth's surface over the south Atlantic Ocean where it dips down to in altitude, and farthest from the Earth's surface over the north Pacific Ocean. If Earth's magnetism is represented by a bar magnet of small size but strong intensity ("magnetic dipole"), the SAA variation can be illustrated by placing the magnet not in the plane of the Equator, but some small distance North, shifted more or less in the direction of Singapore.
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Wilcox, J. M.; Scherrer, P. H.; Hoeksema, J. T., "The origin of the warped heliospheric current sheet" (1980) The waviness of the current sheet is because of the magnetic field dipole axis' tilt angle to the solar rotation axis and variations from an ideal dipole field. Unlike the familiar shape of the field from a bar magnet, the Sun's extended field is twisted into an arithmetic spiral by the magnetohydrodynamic influence of the solar wind. The solar wind travels outward from the Sun at a rate of 200-800km/s, but an individual jet of solar wind from a particular feature on the Sun's surface rotates with the solar rotation, making a spiral pattern in space. Unlike the jet from a sprinkler, the solar wind is tied to the magnetic field by MHD effects, so that magnetic field lines are tied to the material in the jet and take on an arithmetic spiral shape.
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The cause of the ballerina spiral shape has sometimes been called the "garden sprinkler effect" or "garden hose effect",Louise K. Harra, Keith O. Mason, Space Science 2004, Imperial College Press, Smith, E., "The Sun, Solar Wind, and Magnetic Field ", Jul 1999, Proceedings of the International School of Physics Enrico FERMI Varenna, Italy because it is likened to a lawn sprinkler with nozzle that moves up and down while it spins. The stream of water represents the solar wind. The Parker spiral shape of the solar wind changes the shape of the Sun's magnetic field in the outer Solar System: beyond about 10–20 astronomical units from the Sun, the magnetic field is nearly toroidal (pointed around the equator of the Sun) rather than poloidal (pointed from the North to the South pole, as in a bar magnet) or radial (pointed outward or inward, as might be expected from the flow of the solar wind if the Sun were not rotating). The spiral shape also greatly amplifies the strength of the solar magnetic field in the outer Solar System.
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