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Chapter 30

Electromagnetic Induction

التعريفي
التعريفي
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 ...
قانون فاراداي
قانون فاراداي
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 ...
قانون لينز
قانون لينز
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 ...
الحركة EMF
الحركة EMF
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 ...
فاراداي ديسك دينامو
فاراداي ديسك دينامو
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 ...
المجالات الكهربائية المستحثة
المجالات الكهربائية المستحثة
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 ...
المجالات الكهربائية المستحثة: التطبيقات
المجالات الكهربائية المستحثة: التطبيقات
An important distinction exists between the electric field induced by a changing magnetic field and the electrostatic field produced by a fixed charge ...
التيارات الدوامة
التيارات الدوامة
Since eddy currents occur only in conductors, magnets can separate metals from other materials. For example, in a recycling center, trash is dumped in ...
تيار الإزاحة
تيار الإزاحة
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 ...
أهمية تيار الإزاحة
أهمية تيار الإزاحة
A displacement current is analogous to a real current in Ampère's law, participating in Ampère's law the same way as the usual ...
المجالات الكهرومغناطيسية
المجالات الكهرومغناطيسية
Electric fields generated by static charges, often referred to as electrostatic fields, are characteristically different from electric fields created by ...
معادلة ماكسويل للكهرومغناطيسية
معادلة ماكسويل للكهرومغناطيسية
James Clerk Maxwell (1831–1879) was one of the major contributors to physics in the nineteenth century. Although he died young, he made major ...
التماثل في معادلات ماكسويل
التماثل في معادلات ماكسويل
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 ...
قانون أمبير ماكسويل: حل المشكلات
قانون أمبير ماكسويل: حل المشكلات
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 ...
الشكل التفاضلي لمعادلات ماكسويل
الشكل التفاضلي لمعادلات ماكسويل
James Clerk Maxwell (1831–1879) was one of the significant contributors to physics in the nineteenth century. He is probably best known for having ...
المولد الكهربائي: المولد
المولد الكهربائي: المولد
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 ...
مولد التيار المستمر
مولد التيار المستمر
An alternator converts mechanical energy into electrical energy that varies sinusoidally, resulting in AC current. Meanwhile, a DC generator converts ...
EMF الخلفي
EMF الخلفي
Generators convert mechanical energy into electrical energy, whereas motors convert electrical energy into mechanical energy. A motor works by sending a ...
التخميد المغناطيسي
التخميد المغناطيسي
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a ...
موصل فائق
موصل فائق
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a ...
أنواع الموصلات الفائقة
أنواع الموصلات الفائقة
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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