Calculation of Energy stored in a Magnetic Field

For establishing a magnetic field, energy must be spent, though no energy is required to maintain it. take the example of the exciting coils of an electromagnet. The energy supplied to it is spent in two-way (i) part of it goes to meet I2R loss and is lost once for all (ii) part of it goes to create flux and is stored in the magnetic field as potential energy and is similar to the potential energy of a raised weight. When a weight W is raised through a height of…

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Biot-Savart’s Law | Laplace’s Law

Biot Savart’s law is experiment done by Biot and Savart to find magnetic field induction at a point due to small current element. In 1820 Oersted found that when current in passes through a conductor, magnetic field is produced around it. Just at the same time, Laplace gave a rule for calculation magnitude of magnetic field produced. It is known as Laplace’s law or Biot-Savart’s law. Derivation of Biot Savart’s Law Consider a conductor XY through which current I is flowing. Due to it, magnetic field is produced around it.…

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Cyclotron and Synchrotron

The cyclotron is a particle accelerator which is also known as Lawrence cyclotron, As it was conceived by Lawrence in 1929. A cyclotron consists of two large dipole magnets designed to produce a semicircular region of uniform magnetic field, pointing uniformly downward. Because of their D-shape these are called D’s. The two D’s are placed back-to-back with their straight sides parallel but slightly separated, as shown in figure 1. Explanation and Derivation of Cyclotron Now in order to produce an electric field across this gap, we apply an oscillation voltage. Particles,…

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Hall Effect | Hall Effect Derivation

What is Hall Effect? When a sample of conductor carrying, current is placed in a uniform magnetic field perpendicular to the direction of the current, a transverse field will be set up across the conductor. This was first experimentally observed by Edwik H. Hall in 1879. The field developed across the conductor is called Hall field and corresponding potential difference is called Hall voltage and its value is found to depend on the magnetic field strength, nature of the materials and applied current. This type of effect is called Hall…

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Moving Coil Galvanometer

A moving coil galvanometer is a device which is used to detect and measure small electric current. In fact, it is the basic components of most of the measuring instrument including ammeters and voltmeters. It is the most sensitive instrument. Principle: it operation is based on the principle that when a current carrying loop or coil is placed in a uniform magnetic field, the coil experiences a torque. Construction: it consists of a rectangular coil having large number of turns wound on a non-metallic frame. The coil is suspended between…

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Force on Moving Charge in a Magnetic Field

If an electric charge +q moves with a velocity v through a magnetic field B, then magnetic field exerts a force Fm on the charge. Consider the magnetic field acting along y axis, +q charge moves along XY plane making angle θ with the magnetic field. In such case the charge experiences a magnetic force acting along z-axis i.e. perpendicular to the plane of v and B as shown in figure 1. Experimentally it is found that magnitude of magnetic force is with the magnetic field. In such case the…

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Magnetic Field

The first discovery of any connection between electric current and magnetism was made by Oersted in 1820. On one occasion at the end of his lecture, he placed a wire carrying current parallel to a compass needle. To his surprise, the needle was deflected. Upon reversing the current in the wire, the needle deflected in the opposite direction. Oersted concluded that the compass deflection was due to the magnetic field established around the current carrying conductor. The production of magnetism from an electric current which we call electromagnetism has opened…

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Earth’s Magnetic Field | Magnetic Lines of Force

The earth itself behaves like a magnet. A freely suspended bar magnet comes to rest itself roughly along the geographical north-south direction, this is also an evidence to support that fact of earth’s magnetic field. The strength of the earth’s magnetic field is about is 10-4 T or (1G). We can draw magnetic lines of force of earth’s magnetic field on a sheet of paper without placing any magnetic substance in the vicinity. A series of parallel straight lines are obtained directed approximately from geographical south or north. This represent…

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Magnetic Hysteresis

The dictionary meaning of hysteresis is ‘delayed’, here it is the magnetic induction B, which is lagging the magnetizing field H. If an unmagnetised piece of iron placed in a magnetizing field H. if the value of H is increased gradually the magnetic induction B of the iron piece also increases. If a graph is plotted between B and H curve as shown in figure 1 can be obtained in the following way:- Note: Here in this tutorial we had used H for magnetizing field and B for Magnetic Induction At…

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Types of Magnetic Materials

All types of materials and substances posses some kind of magnetic properties which are listed further down in this article. But normally the word “magnetic materials” is used only for ferromagnetic materials ( description below), however, materials can be classified into following categories based on the magnetic properties shown by them: 1. Paramagnetic materials The materials which are not strongly attracted to a magnet  are known as paramagnetic material. For example: aluminium, tin magnesium etc. Their relative permeability is small but positive. For example: the permeability of aluminium is: 1.00000065.…

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