At the terminals of the first wire, connect the battery and the current starts to flow through it. Then he connects the galvanometer to the other wire terminals, with the deflection in the needle of the galvanometer he observed that current is flowing in the secondary windings. He found that the current in the second winding is due to the changing of flux in it. In this method, Faraday gives his famous law. So let's get started with What is Electromagnetic Induction
What is Electromagnetic Induction?
- If a conductor is inserted in the magnetic field and move it in the field due to the flux alteration in the conductor voltage induced in the conductor this aspect is recognized as the electromagnetic induction.
- The voltage can also be induced in the conductive wire if it put in the moving magnetic field and it in static condition.
- If both the field and the conductor are in a state of motion than the voltage can be induced in the conductor.
- Electromagnetic induction based on the Faraday's Law, that says a variation of the flux in any conductive material voltage produced in that conductor.
- This phenomena of voltage production are nowadays is very common in electrical devices and instruments, like a transformer, electric motor and generators.
Faraday’s Law of Electromagnetic Induction
- Faraday's law is the foremost representative that describes electromagnetic induction. Let's discuss it with the detailed.
- This law explains that if either conductor is moving in the field or field is moving than due to flux alteration in the conductor voltage induced in the conductor. The amount of the voltage induce depends on the flux variation.
EMF =dØ/dt
- There are 3 main factors that tell about the magnitude of the voltage induced in the conductor. Let's discuss them one by one.
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- If we increase the number of the turns of the conductive coil it will increase the area of the loop so the larger no of flux lines will pass through the coil and larger amount of the voltage will be induced in the loop.
- If the speed of the coil in the field is increaed than there will be larger emf will induce in the conductor.
- If the conductive loop has constant no of turn and speed if we increase the concentration of the magnetic field then there will be more voltage induced in the coil.
- If we sum all these three points than we have the final equation for Faraday's law.
EMF = N (dø/dt)
- In this equation, the N is the no of turns.
- ø is the flux its unit is weber and its formula is given here.
Ø=BA
- B is the magnetic field.
- A is the area of the conductor.
Electromagnetic Induction in Generator
- Now see how the electromagnetic involve in the generator for power production.
- The simplest structure of the ac generator is constructed in the given figure, it comprises of the magnet that is connected with the shaft when it rotates magnet also rotates with it that produced a rotating field.
- There is a loop of the wire is placed near the magnet that connected with the galvanometer.
- When the shaft magnet rotates its field interact with the loop and induce a voltage in that loop, it is similar to the working principle of the generator.
Lenz’s law of Electromagnetic Induction
- This law explains that the produced in the wire due to variation of the flux has a direction opposite to the field that produce it and opposes any change in it.
- The equation of the Lenz's law is similar to the Faraday's Law it has a minus sign in it. That shows it repels the cause that produces it.
- In simple words, we can say that the current produced in the conductor always resists it cause that induced it in the conductor.
- This law is a fundamental rule for direction finding of the current produced in the conductive element and it is similar to the conservation principle of energy.
- Sometimes current produce due to magnetic induction create a problem as if the current is passing through such conductor that is not the part of our desired circuitry, then the flux of the current passing the conductor creates current this current's flux distorted our main circuit flux this current is also known as the eddy current.
Application of Electromagnetic Induction
- There many applications where phenomena of electromagnetic induction work we discuss its working in the generator and the transformer.
Electromagnetic Induction in Generator
- The working principle of the alternating generator depends on the electromagnetic induction principle.
- The simplest structure of the generator is shown in the given figure. In the figure you can see that the simple loop of the wire is rotating in the field of the bar magnet.
- When the loop rotates in the field the emf induced in the loop according to the phenomena of the magnetic induction.
Electromagnetic Induction in Transformer
- The transformer is a device that is used to step up and step down the voltage level. Its working depends on the phenomena of magnetic induction.
- When the input is provided at the primary windings of the transformer due to flux variation the current is induced in the secondary windings.
