# What are Faraday’s Laws of Electromagnetic Induction?

Before understanding Faraday’s Laws of Electromagnetic Induction, let us first understand the core concept and get its detailed explanation. Electromagnetic induction is the generation of voltage as a result of changes in the magnetic field. To learn more about it, let’s know about Michael Faraday, the man behind these laws.

## Faraday’s Law of Electromagnetic Induction – An introduction

Faraday’s Laws of electromagnetic induction commonly called Faraday’s Laws is the basic law of electromagnetism that aids us in predicting the magnetic field and how it would interact with an electric circuit to generate an electromotive force (EMF). This phenomenon is usually referred to as electromagnetic induction.

Faraday came up with these laws in 1831. Faraday’s Laws of Electromagnetic Induction or the law of electromagnetic induction is, in a way, the outcome of his studies that constituted three experiments on their way to arrive at the electromagnetic induction phenomenon.

Michael Faraday was originally an English scientist who made immense contributions to electromagnetic and electrochemistry research. The concepts underpinning electromagnetic induction, diamagnetism, and electrolysis are among his most important discoveries.

Besides having minimal formal schooling, Faraday was one of the most outstanding scientists in history. Faraday introduced the notion of the electromagnetic field in physics through his studies on the magnetic field surrounding a conductor carrying a direct current. Faraday also demonstrated that magnetism could impact light beams and that there was a link between the two phenomena.

## What are Faraday’s Laws of electromagnetic induction?

The fundamental rule of electromagnetism predicts how a magnetic field would interact with an electric circuit to create an electromotive force (EMF). This is alluded to as electromagnetic induction.

#### More on Faraday’s Laws of Electromagnetic Induction

As we recall, in 1831, Michael Faraday proposed the rules of electromagnetic induction. Faraday’s law is the consequence of Faraday’s experiments. To uncover the phenomena of electromagnetic induction, he conducted three major experiments. Let’s see what those are.

### The First Law of Faraday

The first law of Faraday’s Electromagnetic Induction states that an electromagnetic field is created when a wire is held in a field with a continual change in its magnetic field. This process of electromagnetic field formation is known as an induced EMF. A current is induced within the circuit if it is a closed circuit. “Induced Current” is the technical term for it.

Here are several methods for varying the magnetic field strength in a closed loop:

• By rotating the coil concerning the magnet attraction.
• By altering or adjusting the coil’s position in the magnetic field.
• By varying the area of a coil in a magnetic field.
• By pushing a magnet closer or further away from the coil.

### The Second Law of Faraday

Let us now examine Faraday’s second law. Another Faraday rule on Electromagnetic Induction. According to the law, the induced emf in a conductor is equal to the rate at which the flux is linked to the circuit changes. In this case, the flux is the product of the flux in the wire and the number of turns in the wire.

## The formula for Faraday’s Law

Let us look at how Faraday’s Law came to be. Let us first define certain terms:

Where,

$$\epsilon$$ = the emf or electromotive force

$$\phi$$ = the magnetic flux

N = the total number of turns in the coil

The quantity of electromotive force (ε) created in the circuit is equal to the rate at which the magnetic flux varies through the circuit. The preceding statement or equation can be written as follows:

$$\epsilon = \frac{dt}{d \phi }$$

The difference in potential created throughout an “unloaded loop” is the electromotive force or EMF. This occurs when the resistance in the circuit reaches a critical level. Because EMF and voltage are both measured in voltage, EMF may also be thought of as voltage.

Faraday’s Law is not the only relevant law that defines the electromotive force.

Heinrich Lenz proposed Lenz’s law in 1833. Whereas Faraday’s Law defines the quantity of EMF created within the circuit, Lenz’s Law indicates the direction of current flow inside the circuit. According to the rule, the direction of the current will be opposite to the direction of the flux that created it. In other words, the direction of any magnetic field created by the “induced current” is the inverse of the direction of the real field modification.

Lenz’s Law and Faraday’s Law both reach the same result. The sole distinction is the (minus “-“). This negative sign indicates that the magnetic field direction and the induced emf direction are opposing.

$$\epsilon = – \frac{dt}{d \varphi }$$

If the coil has N turns, then the total magnetic induction in the coil is given as

$$\epsilon = -N \frac{dt}{d \phi }$$

## Faraday’s Experiment

#### Relationship Between Induced EMF and Flux:

The first Faraday’s Law stated that when the overall intensity of the magnetic field changes, only a current is induced in the circuit. This was demonstrated by attaching an ammeter to the wire loop. This ammeter is deflected when the magnet moves in the direction of the wire.

Faraday’s second experiment indicated that when current travels through an iron rod, it becomes electromagnetic. He also discovered that the relative motion of the coil and the magnet produces an induced electromagnetic force.

• When the magnet revolves around its axis, no EMF is created; however, when the magnet rotates on its axis, induced EMF is produced. When the magnet is motionless or set in its place, there is no deflection in the ammeter.
• When the magnet moved close to the coil, the voltage measured increased to its maximum.
• The amount of voltage created as the magnet goes away from the wire is in the opposite direction of the loop.

The third experiment was carried out and documented. When the coil was stationary in this experiment, there was no deflection in the galvanometer. The induced current was therefore created in the coil. However, as the magnet moved away from the circuit, the ammeter deflected away from the loop.

## Faraday’s Law of Derivation

Imagine a magnet that is approaching a coil. Now take into account two-time instances T1 and T2.

Flux linkage with the coil at the time T1 comes from NΦ1.

Flux linkage with the coil at the time T2 is derived from NΦ2

Change in the flux linkage comes from

N(Φ2 – Φ1)

Now, factor in the flux linkage alteration as follows:

Φ = Φ2 – Φ1

Therefore, the flux linkage change comes from,

Now, the rate of change of flux linkage is derived from, NΦ/t

Thus, the derivative of the above equation: N. dΦ/dt

As per Faraday’s second law of electromagnetic induction, we now conclude that the induced emf in a coil is equal to the rate of change of flux linkage. Now, let us consider Lenz’s law:

From the above equation, the conclusions are:

A rise in the number of coil’s turns increases the induced emf

The higher the magnetic field strength, the more the induced EMF is

By raising the pace of the relative motion between the coil and the magnet, EMF increases

#### Lenz’s Law

According to Lenz’s law:

The induced electromotive force with different polarities induces a current whose magnetic field opposes the change in magnetic flux through the loop in order to ensure that the original flux is maintained through the loop when current flows in it.

Lenz’s Law is named after German physicist Emil Lenz. Lenz’s law is based on the principle of conservation of energy and Newton’s third law. It is the most effective way to ascertain the direction of the induced current. As per Lenz’s Law, the direction of the induced current is always such that it is meant to oppose the change in the circuit or the magnetic field that generates it.

Lenz’s Law – Formula

Lenz’s Law reflects itself in the formula of Faraday’s law of electromagnetic induction. The negative sign has been derived from Lenz’s law.

Where:

Emf is the induced voltage (also known as electromotive force).

N is the number of loops.

## Application of Faraday’s Laws

• Faraday’s Law governs the operation of transformers and other electrical equipment.
• The induction cooker works on the idea of reciprocal induction, which is based on Faraday’s Law.
• Inducing an EMF into an electromagnetic flowmeter aids in the recording of liquid flow speed.
• Faraday’s Laws are also used in numerous medical technologies, including MRI scanners, X-ray machines, and CT scanners.

## Conclusion

After doing the above tests, Faraday concluded that if there is relative motion between a wire and a magnetic field, the total amount of flux linkage in the coil varies. This flux shift causes a voltage to be generated in the coil. The law also indicates that the EMF or electromotive force is created as the magnetic flux changes over time. Stay connected to Tutoroot for more interesting articles like this. Register for a plethora of interactive, interesting Physics-related courses as well as limitless personalized assistance.

## FAQ’s

State Faraday’s law of electromagnetic induction

Faraday’s Laws of electromagnetic induction commonly called Faraday’s Laws is the basic law of electromagnetism that aids us in predicting the magnetic field and how it would interact with an electric circuit to generate an electromotive force (EMF). This phenomenon is usually referred to as electromagnetic induction.

What is Faraday’s law of electrolysis?

As per Faraday’s First Law of Electrolysis – The mass of a substance deposited at any electrode is directly proportional to the amount of charge passed

State Faraday’s First Law

The first law of Faraday’s Electromagnetic Induction states that an electromagnetic field is created when a wire is held in a field with a continual change in its magnetic field. This process of electromagnetic field formation is known as an induced EMF. A current is induced within the circuit if it is a closed circuit. “Induced Current” is the technical term for it.

What is Faraday’s Second Law

According to the law, the induced EMF in a conductor is equal to the rate at which the flux is linked to the circuit changes. In this case, the flux is the product of the flux in the wire and the number of turns in the wire.

What is Lenz’s Law?

Lenz’s law, “the polarity of induced emf tends to create a current that opposes the change in magnetic flux that caused it.”

What is Flux?

Flux is the number of electric or magnetic field lines that travel across a surface in a particular length of time.