Electromagnetic Induction

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Real Life Applications

5 min read

- Wondering why to study this chapter? Know the real world use of it!

Electromagnetic Damping in galvanometer:
Certain galvanometers have a fixed core made of nonmagnetic metallic material. When the coil oscillates, the eddy currents are generated in the core. This opposes the motion and bring the coil to rest quickly. Such galvanometers are called dead beat galvanometers because the oscillations die out instantaneously. This is an application of electromagnetic damping effect caused by eddy currents.

Dead Beat Galvanometer | Application of Eddy Current | Physics4Students

2 mins

Alternators in cars:
Ever wondered how headlamps, electric wipers, air conditioner and other accessories are powered in a car? A battery is there, but the power generated by it is not sufficient to operate these loads for a long time. It needs constant recharging. This achieved by installing an alternator which is coupled to the axle of the car. So whenever the car is moving, it rotates the coil in the presence of magnetic field. The varying magnetic flux induces an EMF.
However this induced EMF is sinusoidal in nature. This is converted into DC using a rectifier and then its fed to the battery for charging. This video will explain how alternators, rectifiers and batteries come together to form the charging system in a car.

[HINDI] Car Charging system : Circuit | Working | Animation | Principle

5 mins

Wireless Charging:
Ever wondered how it is possible for mobile batteries to be charged without even plugging it to a power outlet? Electromagnetic Induction makes it possible.
Do you remember Faraday's experiments? Faraday had observed that transient current in the primary coil induces current in the secondary coil. That is what happens in wireless chargers.

Current in the primary transmitter coil generates field around the primary coil
The generated magnetic field induces current in the receiver coil of the device
The induced current is responsible for the charging the device

The same principle will soon be extended to wireless charging of electric vehicles too. Tesla is already on it!

Designing of transformer cores:
Eddy currents are generated in the metallic cores of transformers, electric motors and other such devices in which a coil is to be wound over metallic core through which varying magnetic flux is linked.
Eddy currents are undesirable since they heat up the core and dissipate electrical energy in the form of heat. Magnetic moments of the induced currents depend upon the area enclosed by the currents (

m = I A

)

Thus, eddy currents can be reduced if the area available to the flow of eddy currents is reduced. This is achieved by using the laminated core separated by an insulating material. Since the dissipation of electrical energy into heat depends on the square of the strength of electric current(

H \propto I^{2}

), heat loss is substantially reduced.
NOTE: The plane of the laminations must be arranged parallel to the magnetic field, so that they cut across the eddy current paths.