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Electricity & Megnetism

Can a transformer operate on DC?

A transformer cannot operate on a steady or unchanging dc voltage such as that of a battery.It requires a voltage which rises and falls.Since an ac voltage not only changes its magnitude but its direction as well,it is used to operate the transformers. However,a transformer will operate from dc voltage if this voltage also undergoes changes.Transformers used for audio amplifiers ...

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Eddy current testing principle

What is eddy current? A current induced in a conductor when subject to a varying magnetic field.Such currents are a source of energy dissipation (eddy current loss) in alternating current machinery.The reaction between the eddy currents in a moving conductor and the magnetic in which it is moving is such as to retard the motion.This property of eddy currents is ...

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What are some applications of a step up and step down transformer?

Applications of a step up transformer For Transmission of electric power from power station to consumer,voltage is step up by using step up transformer.It minimizes the power loss in transmission line. Applications of a step down transformer Step down transformer decrease the voltage to a safe value at the end of the transmission line where the consumer of electric power ...

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Why would power distribution systems be less effective without alternating current?

Most larger power distribution systems are AC.The power is transmitted from power stations at much higher voltage to minimize the power loss.At the end of the line where the consumer is located,the voltage level is reduced to a safe value for domestic use.The crucial factor is that it is much easier to increase and decrease AC voltage than DC,so AC ...

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Hall effect and its applications in semiconductors

“An effect when occurring when a current carrying conductor is placed in a magnetic field and orientated so that the field is at right angles to the direction of the current.”This is the Hall effect, named after E. H. Hall who discovered it in 1879.The difference of potential produced is called the Hall emf. An electric field is produced in ...

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Ampere’s law and its applications in daily life

What is ampere’s law? According to this law “The line integral of magnetic field B along a closed path due to current is equal to the product of the permeability of free space and the current enclosed by the closed path”. Mathematically it is expressed as: Where μ0=permeability of free space i=current flowing through the conductor. Proof: Consider a straight ...

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Electric field intensity and electric field lines

“The electric field is a region around a charge in which it exerts electrostatic force on another charges.” According to coulomb’s law ,if a unit positive charge q0 (call it a test charge) is brought near a charge q (call a field charge) placed in space,the charge q0 will experience a force.The value of this force depends upon the distance between ...

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what is Difference between motional and induced emf?

Motional EMF “The emf induced by the motion of a conductor across a magnetic field is called motional emf”. In the previous section we have studied that when conductor is moved across a magnetic field, an emf induced between its ends. The emf of the moving conductor is similar to that of a battery,i.e., if the ends of the conductor ...

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Different types of motors and their applications

What is Electric Motor? An electric motor is an electromechanical device that converts electrical energy into mechanical energy.Electrical motors can be run as generators and vice versa, although this is not always practical. What is the working principle of electric motor? When a current-carrying conductor is located in an external magnetic field perpendicular to the conductor, the conductor experiences a ...

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How materials are magnetized and demagnetized?

What are Magnets? A permanent magnet has a magnetic field surrounding it. A magnet field can be envisioned to consist of lines of force that radiate from the north pole (N) to the south pole (S) and back to the north pole through the magnetic material. A permanent magnet, such as the bar magnet has a magnetic field surrounding it that ...

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