Faraday law Electromagnetic Induction

Faraday law Electromagnetic Induction is shown relation between magnetic circuit and electrical circuit and This law is a basic law of electromagnetism predicting how a magnetic field will be interact with an electrical Circuit to produce an Electromotive force as short name is EMF. This event is called as electromagnetic induction.

This Faraday law Electromagnetic Induction  working principle is mainly used in different type of machine like Transformer,Induction Motor , Generator ,Solenoid etc..


 faraday's law

Faraday law Electromagnetic Induction state that an emf is induced in a given circuit which will be

  1. It is directly proportional to the time rate of change of flux with by the circuit.
  2. It is directly proportional to N the number of turns of the given circuit.

And Lenz’s law of electromagnetic state that in any electrical circuit if it is allowed to flow the current then voltage induced in such a direction that it opposes the cause which produced it and direction of current can be found using Fleming’s right-hand rule..

This law is named given after Michael Faraday . He was the scientist who performed his experiment with magnet and coil.then its experiment gives the direction of the induced EMF and current resulting from electromagnetic induction

Faraday Law Electromagnetic Induction

Faraday’s experiment of electromagnetic induction

  • So far the only way we know of producing in electrical current is by using a battery which is made of chemicals.
  • And this is the fine if you are dealing with the small circuits like in your toy or in your clocks or maybe your mobile phones. but what if you want to distribute electricity on a large scale ?
  • Let’s say you want to distribute electricity to million of the houses around the world. do you build large batteries? imagine the amount of chemicals. what will be mess. so I guess the big question we want to explore now is can be somehow produce electric current without using a batteries, without any chemicals, is it possible? let’s find out.
  • we have already read that if you pass a current through the coil generates a magnetic field generated around it, like a bar magnet which means an electric current can give some magnetic field. but an eager man named Michael Faraday, wondered whether the reverse was possible.
  • Could magnetic fields create electrical current?Because if the answer is yes ,then it’s huge ! because we would have found a new way to create electric current Without using any batteries old chemicals. just by using magnetic fields. so Faraday got excited And he perform a lot of experience to test this.So you want to this.
  • Let’s pretend we are Faraday’s,What kind of experiment would we need to perform to check whether this is true or not? we would require a circuit,To have electrical current in it. basically just coil, with some current sensing device, which can tell us whether there is a current flowing or not.Faraday used of galvanometer.
  • which can tell you whether a current is flowing ,it can also tell you , depending on what direction the deflection is, what direction the current is flowing. but you know what? Galvanometer are boring so let’s use a bulb instead.
  • Let’s assume that our bulb will glow yellowIf current flow in one direction. it will glow blue if the current flow in the opposite direction. that just makes the whole Experience so much more fun,no batteries because we want to check whether we can create electricity E for electrical current without batteries by using magnetic field.
  • and for magnetic field we will require a magnet. so let’s bring in magnet. you can see all circuits in the given figure .
  • Faraday law Electromagnetic Induction
  • places close to this coil and see what happened and we see nothing. there is no glow in the bulb That means there is no current, but there is a magnetic field.Because I have kept a bar magnet close to it. in a magnetic field does not create electrical current. What a disappointed .
  • So let’s pick up and go home let’s throw away the magnet. where I just saw a flash of light. let’s bring back the magnet.
  • Wow, we saw a flash again. Figur This time it was blue,Show the current was in the opposite direction. but we did it. we create electricity without batteries for split second.
  • but it’s seem to work only when the magnet is moving, not when it is at rest. and as a Faraday I raise my eyebrows and I say,”hmmm Interesting”. now let’s play with this even more.
  • What if we keep magnet addressed in the coil instead?Do you think we will create electricity again? you are guys is a good as mine so let’s see and Bingo! Figur there was have it.Again we save a flash of light when the coil was moving.
  • so this means that if it is the coil for the magnet one of them have to move and during the motion we are getting electricity.
  • What they had discovered through this experiment, is that a study magnetic field does not generate an electrical current,But a changing magnetic field does. Show the current that is produced over here, we can also say a voltage is produced because of which the charges are moving and we are getting a current.
  • Due to changing magnetic field we call them as an induced current or induced voltage.
  • To differentiate from the current and the voltage. we get from a battery. and this phenomenon is called electromagnetic induction.
  • So electromagnetic induction is a phenomenon in which when you change the magnetic field through a coil , it induced a voltage or current and when Faraday presented his discovery Faraday law Electromagnetic Induction.
  • One person asking him, so what? Changing magnetic field produces a voltage. what is the big deal? Faraday Said,’’one day this will be power up our whole world”.Faraday law Electromagnetic Induction

Faraday’s First Law 

State faraday’s law of electromagnetic induction that Whenever a conductor is placed in a changing magnetic field and it EMF is gets induced across the conductor and also called as induced emf., and if the conductor is a closed circuit then induced current will be flowing through it.

Magnetic field can be changed by different types of methods –

1. By moving a magnet toward near coil or away from the coil.

2. By moving the coil near to magnet.

3. By rotating the coil relative to the magnetic field or magnetic flux

Faraday’s Second Law of Electromagnetic Induction

Faraday’s second law of electromagnetic induction states that the magnitude of the induced emf given circuit is equal to the rate of change of flux linkages with the coil.

The flux linkages is the product of number of the coil of the conductor and the flux allies with the coil.

Faraday law formula

Let’s consider conductor moving toward magnetic field,

✔ Now flux linkage with coil at initial position of the conductor is,

1

✔ Flux linkage with coil at last (final) position of the conductor is,

2

✔ It change in flux linkage from initial position to final position,

N(Φ1 – Φ2)

✔ Lets take,

Φ =Φ1 – Φ2

✔ So ,Change in flux linkage will be

✔ Now rate of change of flux linkage with

NΦ/t

✔ Take derivative at right-hand side(RHS) then we will get ,

N dΦ/dt

✔ So finely according faraday’s law rate of change of flux linkages is equal to the induced emf,

E=  N dΦ/dt

✔ Consider lanz law is,

E= ⧿ N dΦ/dt

Application of Faraday’s Law

Faraday law Electromagnetic Induction is most using common important law of electromagnetism.This law are using in application in machine like transformer ,induction motor ,electrical field ,various industries , etc.

✔ Faraday’s Law used in Electromagnetic Flow Meter.

✔ Power Transformer is working on function of Faraday’s Law.

✔ It is used in Induction Cooker with work on function of mutual induction.


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