Induced Electromotive Force and Current

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What is Induced Electromotive Current?

Induced electromotive current is the induction of current in the loop just by changing the magnetic field. In Faraday’s law, there are some experiments which are based on this theory. In the first experiment, we have noticed that the ammeter shows zero current reading which generally means or proves that a stationary magnet does not induce a current in a coil. In the second experiment, we have noticed that the meter shows the induction the current which demonstrates that it is due to the change in the magnetic field as the magnet is moved towards or we can say away from the coil.

So it is very clear to us that a constant magnetic field generally does nothing to the coil while we can say that a changing field causes current to flow.

Hence we can gain an observation from the above experiments that we have discussed that only by changing a magnetic field we can make the current flow. To be more accurate we can say that if the magnetic flux through a coil is changed then a voltage will be produced. This voltage is called the induced emf. 

Based on his understanding of electromagnets we can say that he expected that when current started to flow in one wire a sort of wave would travel through the ring and then cause some electrical effect on the opposite side. He plugged one wire that too into a galvanometer and then watched it as he connected the other wire to a battery as well. He saw a transient current which he for himself called as a "wave of electricity". when he connected the wire with the battery and another when he disconnected it. Within two months the scientist named Faraday found several other manifestations of electromagnetic induction


Induced Electromotive Force

The Magnetic flux is generally linked with the surface area when it is held inside the magnetic field. We can say that when the direction of the magnetic field is perpendicular to the surface area then the flux of magnet or we can say that the magnetic flux on the surface is more. When the magnetic field is said to be parallel to the surface area, then the magnetic flux is on the surface which is less.

Have you ever wondered that when the coil completely remains inside the magnetic field that too during motion then why no current flows through it?

When the coil is said to be entirely inside the magnetic field, one of the two ends of the coil becomes positive and the other end of the coil becomes negative. The potential difference which is between the coils will be equal in each case. So when two cells that are having equivalent electromotive force are connected to each other then we can say that no current flows through the coil, and no net induced electromotive force exists in the coil.

The law of Lenz's describes the direction which is of the induced field. 


Induced Electromotive Force and Current

Faraday's law that generally describes two different phenomena that is the motional EMF generated by a force which is the magnetic force on a moving wire and the transformer that is of the EMF this is generated by an electric force due to a changing magnetic field that too due to the differential form of the Maxwell–Faraday equation. In 1861, James Clerk Maxwell drew attention to this separate physical phenomena. This is believed or said to be a unique example in physics of where such a fundamental law is invoked to explain two such different phenomena.


Do You Know?

What happens when the string of the electric guitar which we use to play vibrates? 

When the string of an electric guitar vibrates then we can say that an electromotive force is introduced in the coil. The induced magnetization which is present in the string is picked up from the vibration of the guitar. The input which is of an amplifier that is of the guitar is connected to the two ends of the coil which are connected to the speakers.

Stay tuned to Vedantu to learn more about emf, induced electromotive force, and much more.

FAQ (Frequently Asked Questions)

1. What is an induced electromotive force?

Any change in magnetic flux induces an electromotive force that is EMF opposing that change which is a process called induction. The motion is one of the major causes that are of induction. For example, we can say that a magnet moved toward a coil induces an EMF and a coil moved toward a magnet produces a similar EMF.

2. Is induced emf the same as induced current?

We can say the greater the rate of change of flux the larger is the induced emf. In the magnet which is moving the magnetic flux through the coil changes and this changing flux produces the induced current in the coil. We can say that when the magnet moves away from the coil a current that is again induced but now in the direction which is opposite.

3. Explain what do you mean by induced current and induced EMF.

We can say that an induced current has a direction such that the field which is of the magnet due to the induced current opposes the change in the magnetic flux that induces the current. The same thing as the saying of different scientists. An induced emf generally is said to act to oppose the change that produces it.

4. What is the formula for electromotive force EMF?

The emf which we already know is equal to the work done on the charge per unit charge given by ϵ=dWdq, when there is no current flowing. Since we can say that the unit for work is the joule and the unit for charge is the coulomb so we observe that the unit for emf is the volt given by 1V=1J/C.