The simplest type of electromagnet is a coiled piece of wire. A coil forming the shape of a straight tube (similar to a corkscrew) is called a solenoid; a solenoid that is bent so that the ends meet is a toroid. Much stronger magnetic fields can be produced if a "core" of paramagnetic or ferromagnetic material (commonly iron) is placed inside the coil. The field produced by the coil causes the iron to magnetize and generate a field of its own. This field can be hundreds or thousands o ...

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Electromagnet, Electromagnet - Introduction, Electromagnet - Electromagnets and permanent magnets, Electromagnet - Devices that use electromagnets, Electromagnet - Force on ferromagnetic materials

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Electromagnet, Electromagnet - Introduction, Electromagnet - Electromagnets and permanent magnets, Electromagnet - Devices that use electromagnets, Electromagnet - Force on ferromagnetic materials

Read more here: » Electromagnet: Encyclopedia II - Electromagnet - Electromagnets and permanent magnets

Electromagnets are used in many situations where a rapidly or easily variable magnetic field is desired. Many of these applications involve deflection of charged particle beams; the cathode ray tube and mass spectrometer fall into this category. Other devices cause electromagnetic fields to interact with fields from permanent magnets and produce forces. Electromagnetic actuators take advantage of the fact that, if the core of a solenoid is displaced toward one end of the coil, a force will occur tending to push the core farther in tha ...

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Electromagnet, Electromagnet - Introduction, Electromagnet - Electromagnets and permanent magnets, Electromagnet - Devices that use electromagnets, Electromagnet - Force on ferromagnetic materials

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A magnet is an object that has a magnetic field. The word magnet comes from the Greek "magnítis líthos" (μαγνήτης λίθος), which means "magnesian stone". Magnesia is an area in Greece (Now Manisa, Turkey) where deposits of magnetite have been discovered since antiquity. Magnet - Introduction. In the modern sense, a magnet is any material that has a magnetic field. It can be in the form of a permanent magnet or an electromagnet. Permanent magnets do not rely upon outside in ...

Including:

Magnet - Introduction Magnet - Physical origin of magnetism
Magnet - Permanent Magnets Magnet - Electromagnets
Magnet - Characteristics of magnetic materials
Magnet - Permanent magnets and dipoles Magnet - North/south pole designation and the Earth's magnetic field
Magnet - Common uses for magnets Magnet - How to magnetize materials Magnet - How to demagnetize materials Magnet - Types of permanent magnets Magnet - Magnetic forces
Magnet - Magnets and other magnets Magnet - Magnets and ferromagnetic materials Magnet - Magnets and diamagnetic materials Magnet - Magnets and paramagnetic materials Magnet - Calculating the magnetic force
Magnet - Online references Magnet - Printed references Magnet - External articles

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Magnet - Permanent magnets. All normal matter is composed of particles (protons, neutrons, and electrons), and all of these particles have the fundamental property of quantum mechanical spin. Spin gives each one of these particles an associated magnetic field. Because of this, and the fact that the average microscopic piece of matter contains huge numbers of these particles, it would be expected that all matter would be magneti ...

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Magnet, Magnet - Introduction, Magnet - Physical origin of magnetism, Magnet - Permanent magnets, Magnet - Electromagnets, Magnet - Characteristics of magnetic materials, Magnet - Permanent magnets and dipoles, Magnet - North/south pole designation and the Earth's magnetic field, Magnet - Common uses for magnets, Magnet - How to magnetize materials, Magnet - How to demagnetize materials, Magnet - Types of permanent magnets, Magnet - Magnetic forces, Magnet - Magnets and other magnets, Magnet - Magnets and ferromagnetic materials, Magnet - Magnets and diamagnetic materials, Magnet - Magnets and paramagnetic materials, Magnet - Calculating the magnetic force, Magnet - Online references, Magnet - Printed references, Magnet - External articles

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Magnet - Permanent magnets and dipoles. All magnets are dipoles: that is, all magnets have a north and a south pole. The poles are not a pair of things on or inside the magnet. They are a concept used to discuss and describe magnets. In the image at the top of this page, the poles look like specific locations (because the highest surface intensity of the field occurs at the poles), ...

See also:

Magnet, Magnet - Introduction, Magnet - Physical origin of magnetism, Magnet - Permanent magnets, Magnet - Electromagnets, Magnet - Characteristics of magnetic materials, Magnet - Permanent magnets and dipoles, Magnet - North/south pole designation and the Earth's magnetic field, Magnet - Common uses for magnets, Magnet - How to magnetize materials, Magnet - How to demagnetize materials, Magnet - Types of permanent magnets, Magnet - Magnetic forces, Magnet - Magnets and other magnets, Magnet - Magnets and ferromagnetic materials, Magnet - Magnets and diamagnetic materials, Magnet - Magnets and paramagnetic materials, Magnet - Calculating the magnetic force, Magnet - Online references, Magnet - Printed references, Magnet - External articles

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Capacitance is a measure of the amount of electric charge stored (or separated) for a given electric potential. The capacitance is usually defined as the total electric charge placed on the object divided by the potential of the object: or, according to Gauss's law, the capacitance can be expressed as the electric flux per volt where C is the capacitance in farads Q is the charge in coulombs ...

Including:

Capacitance - Definition Capacitance - Introduction Capacitance - Energy Capacitance - Capacitance and 'displacement current' Capacitance - Capacitance/inductance duality Capacitance - Self-capacitance

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A space observatory is any instrument in outer space which is used for observation of distant planets, galaxies, and other outer space objects. Space observatory - Introduction. A large number of observatories have been launched into orbit, and most of them have greatly enhanced our knowledge of the cosmos. Performing astronomy from the Earth's surface is limited by the filtering and distortion of electromagnetic radiation due to the Earth's atmosphere. This makes it desirable to place astrononomical ...

Including:

Space observatory - Introduction Space observatory - NASA's Great Observatories Space observatory - Other notable space observatories Space observatory - Future space observatories

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A Bose-Einstein condensate is a phase of matter formed by bosons cooled to temperatures very near to absolute zero. The first such condensate was produced by Eric Cornell and Carl Wieman in 1995 at the University of Colorado at Boulder, using a gas of rubidium atoms cooled to 170 nanokelvins (nK). Under such conditions, a large fraction of the atoms collapse into the lowest quantum state. Bose-Einstein condensate - Introduction. Bose-Einstein condensates are best known to laymen as extremely low temperature ...

Including:

Bose-Einstein condensate - Introduction Bose-Einstein condensate - Theory Bose-Einstein condensate - Discovery Bose-Einstein condensate - Unusual characteristics Bose-Einstein condensate - Current research

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Quantum mechanics is a fundamental physical theory that replaces Newtonian mechanics and classical electromagnetism at the atomic and subatomic levels and is the underlying framework of many fields of physics and chemistry, including condensed matter physics, quantum chemistry, and particle physics. Along with general relativity, it is one of the pillars of modern physics. Quantum mechanics - Introduction. The term quantum (Latin, "how much") refers to the discrete units that the theory assign ...

Including:

Quantum mechanics - Introduction Quantum mechanics - Description of the theory
Quantum mechanics - Quantum mechanical effects Quantum mechanics - Mathematical formulation Quantum mechanics - Interactions with other scientific theories
Quantum mechanics - Applications of quantum theory Quantum mechanics - Philosophical consequences Quantum mechanics - History
Quantum mechanics - Founding experiments
Quantum mechanics - Notes

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Bioelectromagnetics is the study of how electromagnetic fields interact with and influence biological processes. Common areas of investigation include the mechanism of animal migration and navigation using the geomagnetic field, studying the potential effects of man-made sources of electromagnetic fields, such as those produced by the power distribution system and mobile phones, and developing novel therapies to treat various conditions. While several treatments based on the use of magnetic fields have been reported in peer-reviewed j ...

Including:

Bioelectromagnetics - Introduction: general features of observed interactions
Bioelectromagnetics - Thermal vs nonthermal nature Bioelectromagnetics - Noise-masking time and space integration cooperativity Bioelectromagnetics - Intrinsic fields Bioelectromagnetics - Natural fields
Bioelectromagnetics - Primary interaction mechanisms
Bioelectromagnetics - Membrane polarization Bioelectromagnetics - Electrorotation Bioelectromagnetics - Ion cyclotron resonance and ion parametric resonance Bioelectromagnetics - Nonlinear kinetics Bioelectromagnetics - Frohlich-style macro dipole interactions Bioelectromagnetics - DNA conduction Bioelectromagnetics - Microtubule waveguides Bioelectromagnetics - Ferromagnetic domains Bioelectromagnetics - Frequency selectivity from spatial features
Bioelectromagnetics - Effects on the level of a cell or below
Bioelectromagnetics - Calcium efflux Bioelectromagnetics - Neurotransmitter systems Bioelectromagnetics - DNA strand breaks and genotoxicity Bioelectromagnetics - Ornithine decarboxylase Bioelectromagnetics - Melatonin Bioelectromagnetics - Bacterial growth and metabolism
Bioelectromagnetics - Effects on the level of an organ or system
Bioelectromagnetics - Blood-brain barrier permittivity Bioelectromagnetics - EEG changes Bioelectromagnetics - Wound healing regeneration and bone growth Bioelectromagnetics - Cancer promotion
Bioelectromagnetics - Whole-organism effects
Bioelectromagnetics - Electrical sensing organs fish etc Bioelectromagnetics - Navigation bees pidgeons etc Bioelectromagnetics - Effects on embryonic development Bioelectromagnetics - Behavioral effects
Bioelectromagnetics - Effects of artificial fields
Bioelectromagnetics - Powerlines Bioelectromagnetics - CRTs Bioelectromagnetics - Cell phones Bioelectromagnetics - Radar Bioelectromagnetics - Other transmitters radio TV ...
Bioelectromagnetics - Medical applications
Bioelectromagnetics - Bone fracture healing Bioelectromagnetics - TMS and related Bioelectromagnetics - Low-level Laser Therapy LLLT Bioelectromagnetics - Strong magnetic pulses for disinfection Bioelectromagnetics - Other

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Permanent magnets can be demagnetized in the following ways: Heat. Heating a magnet past its Curie point will destroy the long range ordering. Contact. Stroking one magnet with another in random fashion will demagnetize the magnet being stroked, in some cases; some materials have a very high coercive field and cannot be demagnetized with other permanent magnets. Hammering or jarring. Such activity will destroy the long range ordering within the magnet. Being placed in a solenoid which has an alternatin ...

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Magnet, Magnet - Introduction, Magnet - Physical origin of magnetism, Magnet - Permanent magnets, Magnet - Electromagnets, Magnet - Characteristics of magnetic materials, Magnet - Permanent magnets and dipoles, Magnet - North/south pole designation and the Earth's magnetic field, Magnet - Common uses for magnets, Magnet - How to magnetize materials, Magnet - How to demagnetize materials, Magnet - Types of permanent magnets, Magnet - Magnetic forces, Magnet - Magnets and other magnets, Magnet - Magnets and ferromagnetic materials, Magnet - Magnets and diamagnetic materials, Magnet - Magnets and paramagnetic materials, Magnet - Calculating the magnetic force, Magnet - Online references, Magnet - Printed references, Magnet - External articles

Read more here: » Magnet: Encyclopedia II - Magnet - How to demagnetize materials

Magnetized items interact with other items in very specific ways. Magnet - Magnets and other magnets. If a magnet is brought close enough to another magnet, their fields will begin to interact in the following ways: If each magnets north pole is brought together, the magnets will repel one another (like poles repel) If the north pole of one magnet is brought to the south pole of the other magnet (or vice versa), the magnets will attract one another (opposite poles attract) Magnet - M ...

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Magnet, Magnet - Introduction, Magnet - Physical origin of magnetism, Magnet - Permanent magnets, Magnet - Electromagnets, Magnet - Characteristics of magnetic materials, Magnet - Permanent magnets and dipoles, Magnet - North/south pole designation and the Earth's magnetic field, Magnet - Common uses for magnets, Magnet - How to magnetize materials, Magnet - How to demagnetize materials, Magnet - Types of permanent magnets, Magnet - Magnetic forces, Magnet - Magnets and other magnets, Magnet - Magnets and ferromagnetic materials, Magnet - Magnets and diamagnetic materials, Magnet - Magnets and paramagnetic materials, Magnet - Calculating the magnetic force, Magnet - Online references, Magnet - Printed references, Magnet - External articles

Read more here: » Magnet: Encyclopedia II - Magnet - Magnetic forces

Magnet - Permanent magnets and dipoles. All magnets have at least two poles: that is, all magnets have at least one north pole and at least one south pole. The poles are not a pair of things on or inside the magnet. They are a concept used to discuss and describe magnets. In the image at the top of this page, the poles look like specific locations (because the highest surface intensity of the field occurs at the poles), ...

See also:

Magnet, Magnet - Introduction, Magnet - Physical origin of magnetism, Magnet - Permanent magnets, Magnet - Electromagnets, Magnet - Characteristics of magnetic materials, Magnet - Permanent magnets and dipoles, Magnet - North/south pole designation and the Earth's magnetic field, Magnet - Common uses for magnets, Magnet - How to magnetize materials, Magnet - How to demagnetize materials, Magnet - Types of permanent magnets, Magnet - Magnetic forces, Magnet - Magnets and other magnets, Magnet - Magnets and ferromagnetic materials, Magnet - Magnets and diamagnetic materials, Magnet - Magnets and paramagnetic materials, Magnet - Calculating the magnetic force, Magnet - Online references, Magnet - Printed references, Magnet - External articles

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Hysteresis phenomena occur in magnetic and ferromagnetic materials, as well as in the elastic and electromagnetic behavior of materials, in which a lag occurs between the application and the removal of a force or field and its subsequent effect. Electric hysteresis occurs when applying a varying electric field, and elastic hysteresis occurs in response to a varying force. If the displacement of a system with hysteresis is plotted on a graph against the applied force, the resulting curve is in the form of a loop. In contrast, the curve ...

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Hysteresis, Hysteresis - Introduction, Hysteresis - Informal Definition, Hysteresis - Magnetic hysteresis, Hysteresis - Electrical hysteresis, Hysteresis - Liquid-solid phase transitions, Hysteresis - Energy, Hysteresis - Economics, Hysteresis - User interface design, Hysteresis - Electronics, Hysteresis - Applications

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The field tensor derives its name from the fact that the electromagnetic field is found to obey the tensor transformation law, this general property of (non-gravitational) physical laws being recognised after the advent special relativity. This theory stipulated that all the (non-gravitational) laws of physics should take the same form in all coordinate systems - this led to the introduction of tensors. The tensor formalism also leads to a mathematically elegant presentation of physical laws. For example, Maxwell's equations ...

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Electromagnetic tensor, Electromagnetic tensor - Details, Electromagnetic tensor - Derivation, Electromagnetic tensor - Significance of the Field Tensor, Electromagnetic tensor - The field tensor and relativity, Electromagnetic tensor - Role in Quantum Electrodynamics and Field Theory

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Capacitance is a measure of the amount of electric charge stored (or separated) for a given electric potential. The capacitance is usually defined as the total electric charge placed on the object divided by the potential of the object: or, according to Gauss's law, the capacitance can be expressed as the electric flux per volt where C is the capacitance in farads Q is the charge in coulombs ...

See also:

Capacitance, Capacitance - Definition, Capacitance - Introduction, Capacitance - Energy, Capacitance - Capacitance and 'displacement current', Capacitance - Capacitance/inductance duality, Capacitance - Self-capacitance

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Capacitance exists between any two conductors insulated from one another. The formula defining capacitance above is valid if it is understood that the conductors have equal but opposite charge Q, and the voltage V is the potential difference between the two conductors. The SI unit of capacitance is the farad (F). A capacitance of one farad results in a potential of one volt for one coulomb of charge. The capacitance of the majority of capacitors used in electronic circuits is several orders of magnitude smaller than the farad. The most common units of capacitance in use today are the microfarad (µF) ...

See also:

Capacitance, Capacitance - Definition, Capacitance - Introduction, Capacitance - Energy, Capacitance - Capacitance and 'displacement current', Capacitance - Capacitance/inductance duality, Capacitance - Self-capacitance

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The energy (measured in joules) stored in a capacitance is equal to the work done to charge it. Consider a capacitance C, holding a charge +q on one plate and -q on the other. Moving a small element of charge dq from one plate to the other against the potential difference V = q/C requires the work dW: where W is the work measured in joules q is the charge measured in coulombs C is the ...

See also:

Capacitance, Capacitance - Definition, Capacitance - Introduction, Capacitance - Energy, Capacitance - Capacitance and 'displacement current', Capacitance - Capacitance/inductance duality, Capacitance - Self-capacitance

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In electrical circuits, the term capacitance is usually a shorthand for the mutual capacitance between two adjacent conductors, such as the two plates of a capacitor. There also exists a property called self-capacitance, which is the amount of electrical charge that must be added to an isolated conductor to raise its electrical potential by one volt. The reference point for this potential is a theoretical hollow conducting sphere, of infinite radius, centred on the conductor. Using this method, the self-capacitance of a conducting sphere of radius R is given by: CSee also:

Capacitance, Capacitance - Definition, Capacitance - Introduction, Capacitance - Energy, Capacitance - Capacitance and 'displacement current', Capacitance - Capacitance/inductance duality, Capacitance - Self-capacitance

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