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Kapitel 30

Electromagnetic Induction

Induktion
Induktion
An emf is induced when the magnetic field in a coil is changed by pushing a bar magnet into or out of the coil. emfs of opposite signs are produced by ...
Faradaysches Gesetz
Faradaysches Gesetz
Faraday's law state that the induced emf is the negative change in the magnetic flux per unit of time. Any change in the magnetic field or change in ...
Das Lenzsche Gesetz
Das Lenzsche Gesetz
The direction in which the induced emf drives the current around a wire loop can be found through the negative sign. However, it is usually easier to ...
Bewegungsbedingte EMK
Bewegungsbedingte EMK
Magnetic flux depends on three factors: the strength of the magnetic field, the area through which the field lines pass, and the field's orientation ...
Faraday Disk Dynamo
Faraday Disk Dynamo
A Faraday disk dynamo is a DC generator, producing an emf that is constant in time. It consists of a conducting disk that rotates with a constant angular ...
Induzierte elektrische Felder
Induzierte elektrische Felder
The fact that emfs are induced in circuits implies that work is being done on the conduction electrons in the wires. What can possibly be the source of ...
Induzierte elektrische Felder: Anwendungen
Induzierte elektrische Felder: Anwendungen
An important distinction exists between the electric field induced by a changing magnetic field and the electrostatic field produced by a fixed charge ...
Wirbelströme
Wirbelströme
Since eddy currents occur only in conductors, magnets can separate metals from other materials. For example, in a recycling center, trash is dumped in ...
Verschiebungsstrom
Verschiebungsstrom
Ampère's law, in its usual form, does not work in places where the current changes with time and is not steady. Thus, Maxwell suggested including ...
Bedeutung des Verschiebungsstroms
Bedeutung des Verschiebungsstroms
A displacement current is analogous to a real current in Ampère's law, participating in Ampère's law the same way as the usual ...
Elektromagnetische Felder
Elektromagnetische Felder
Electric fields generated by static charges, often referred to as electrostatic fields, are characteristically different from electric fields created by ...
Maxwells Gleichung des Elektromagnetismus
Maxwells Gleichung des Elektromagnetismus
James Clerk Maxwell (1831–1879) was one of the major contributors to physics in the nineteenth century. Although he died young, he made major ...
Symmetrie in den Maxwell-Gleichungen
Symmetrie in den Maxwell-Gleichungen
Once the fields have been calculated using Maxwell's four equations, the Lorentz force equation gives the force that the fields exert on a charged ...
Ampere-Maxwell-Gesetz: Problemlösung
Ampere-Maxwell-Gesetz: Problemlösung
A parallel-plate capacitor with capacitance C, whose plates have area A and separation distance d, is connected to a resistor R and a battery of voltage ...
Differentialform der Maxwell-Gleichungen
Differentialform der Maxwell-Gleichungen
James Clerk Maxwell (1831–1879) was one of the significant contributors to physics in the nineteenth century. He is probably best known for having ...
Elektrischer Generator: Lichtmaschine
Elektrischer Generator: Lichtmaschine
Electric generators induce an emf by rotating a coil in a magnetic field. A simple alternator is an AC generator that creates electrical energy that ...
DC-Generator
DC-Generator
An alternator converts mechanical energy into electrical energy that varies sinusoidally, resulting in AC current. Meanwhile, a DC generator converts ...
Gegen-EMK
Gegen-EMK
Generators convert mechanical energy into electrical energy, whereas motors convert electrical energy into mechanical energy. A motor works by sending a ...
Magnetische Dämpfung
Magnetische Dämpfung
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a ...
Supraleiter
Supraleiter
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a ...
Arten von Supraleitern
Arten von Supraleitern
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the ...
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