Electromagnetic induction. Induced current, Faraday’s and Lenz’s laws and applications

08/05/2026

The online electromagnetic induction simulations on this page will allow you to learn more about this important phenomenon of electromagnetism. We will discover how induced electric current is generated, what Faraday’s law and Lenz’s law tell us and we will also see some of the most important applications

This Thematic Unit is part of our Physics collection

Coil (Inductor)

Component consisting of a wound conducting wire that stores energy in the form of a magnetic field when current flows through it.

Electromagnetic Induction

Process by which an electric current is generated in a conductor when it is exposed to a changing magnetic field.

Electromotive Force (EMF)

Potential difference generated by a non-electrical source (such as a changing magnetic field), measured in Volts (V) in the SI.

Faraday’s Law

Law stating that the induced electromotive force (EMF) is proportional to the rate of change of magnetic flux: ε = -dΦ / dt.

Lenz’s Law

Principle indicating that the induced current flows in a direction such that its magnetic field opposes the change in flux that produced it.

Magnetic Flux

Measure of the amount of magnetism passing through a surface, calculated as Φ = B · A · cos(θ) and measured in Webers (Wb) in the SI.

What is electromagnetic induction

Electromagnetic induction is the process by which an electric current, called induced current, is produced in a conductor when it is exposed to a magnetic field that changes with time. This induced current is produced due to the interaction between the magnetic field and the electrons in the conductor.

The phenomenon of electromagnetic induction was discovered by Michael Faraday in 1831, who observed that moving a magnet inside a coil of wire generated an induced electric current in the wire. This discovery laid the foundation for the generation of electricity on a large scale.

Laws of electromagnetic induction

To fully understand the phenomenon of electromagnetic induction, it is essential to know two fundamental laws: Faraday’s law and Lenz’s law. Together, they provide the theoretical framework for understanding and predicting the behavior of electromagnetic systems in everyday life and in technological applications.

Faraday’s law

Faraday’s law states that the magnitude of the electromotive force induced in a circuit is proportional to the change in magnetic flux through the circuit. Magnetic flux is defined as the product of the magnetic field and the area perpendicular to it. Therefore, when a conductor moves through a magnetic field that changes with time, the magnetic flux through the conductor changes, which produces an induced electric current in the conductor.

Lenz’s law

Lenz’s law complements Faraday’s law by establishing the direction of the induced current. It states that the induced current in a circuit is always generated in such a direction that its magnetic field opposes the change in the magnetic flux that produces it. This principle, formulated by the Russian physicist Heinrich Lenz in 1834, guarantees the conservation of energy and explains phenomena such as magnetic braking and opposition to motion in generators and electric motors. Thanks to Lenz’s law, it is not only known how much voltage is induced, but also in which direction the induced current flows, which is essential for the design and operation of many electromagnetic devices.

Applications of electromagnetic induction

Electromagnetic induction is used in a wide range of applications, including electric generators, transformers and electric motors. Electric generators use electromagnetic induction to convert mechanical energy into electrical energy. Electric motors, on the other hand, use the electric current generated by electromagnetic induction to produce motion.

Electromagnetic induction is also used in electronic devices such as magnetic card readers or wireless technologies, such as wireless chargers, which use induction to transfer energy through magnetic fields.

Coil (Inductor)

Component consisting of a wound conducting wire that stores energy in the form of a magnetic field when current flows through it.

Electromagnetic Induction

Process by which an electric current is generated in a conductor when it is exposed to a changing magnetic field.

Electromotive Force (EMF)

Potential difference generated by a non-electrical source (such as a changing magnetic field), measured in Volts (V) in the SI.

Faraday’s Law

Law stating that the induced electromotive force (EMF) is proportional to the rate of change of magnetic flux: ε = -dΦ / dt.

Lenz’s Law

Principle indicating that the induced current flows in a direction such that its magnetic field opposes the change in flux that produced it.

Magnetic Flux

Measure of the amount of magnetism passing through a surface, calculated as Φ = B · A · cos(θ) and measured in Webers (Wb) in the SI.

Explore the exciting STEM world with our free, online, simulations and accompanying companion courses! With them you’ll be able to experience and learn hands-on. Take this opportunity to immerse yourself in virtual experiences while advancing your education – awaken your scientific curiosity and discover all that the STEM world has to offer!

Electromagnetic induction simulations

Moving bar

Principle of electromagnetic induction

This simulation allows us to observe the working principle of electromagnetic induction. The movement of the magnet changes the magnetic field of the inductor, which generates an electric current in the coil.

Rotating coil

Faraday’s Law

Investigate Faraday’s Law and how changing the magnetic flux can produce a flow of electricity.

Giants of science

“If I have seen further, it is by standing on the shoulders of giants”

Isaac Newton

Michael Faraday

1791

–

1867

Michael Faraday discovered electromagnetic induction, conducted pioneering experiments in optics (Faraday effect), and established fundamental principles of electrochemistry.

“Nothing is too wonderful to be true”

James Clerk Maxwell

1831

–

1879

James Clerk Maxwell formulated Maxwell’s equations, unifying electricity and magnetism and predicting electromagnetic waves

“Thoroughly conscious ignorance is the prelude to every real advance in science”

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“If I have seen further, it is by standing on the shoulders of giants”

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James Clerk Maxwell

1831

–

1879

James Clerk Maxwell formulated Maxwell’s equations, unifying electricity and magnetism and predicting electromagnetic waves

“Thoroughly conscious ignorance is the prelude to every real advance in science”

Michael Faraday

1791

–

1867

Michael Faraday discovered electromagnetic induction, conducted pioneering experiments in optics (Faraday effect), and established fundamental principles of electrochemistry.

“Nothing is too wonderful to be true”

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Test your knowledge

What is electromagnetic induction, and why is it essential for electricity generation?

Electromagnetic induction is the process by which an electric current is produced in a conductor when the magnetic flux through it changes over time. Discovered by Michael Faraday in 1831, it forms the foundation of modern electricity generation. When a magnet moves near a coil, or when the coil moves within a changing magnetic field, the electrons in the conductor experience a force that sets them in motion, creating an induced current. The magnitude of this current depends on how quickly the magnetic flux changes and on the characteristics of the circuit. Electromagnetic induction allows mechanical energy to be converted into electrical energy, enabling the operation of generators, transformers and many electromagnetic devices. Without this phenomenon, large‑scale production and distribution of electricity would not be possible.

How do Faraday’s Law and Lenz’s Law explain the behavior of induced current in a circuit?

Faraday’s Law states that the induced electromotive force in a circuit is proportional to the rate of change of magnetic flux through it. This means that faster changes in the magnetic field produce stronger induced voltages. Magnetic flux depends on the strength of the field, the area of the circuit and their relative orientation. However, Faraday’s Law does not specify the direction of the induced current; that is determined by Lenz’s Law. According to Lenz’s Law, the induced current always flows in a direction that opposes the change in magnetic flux that caused it. This ensures conservation of energy and explains effects such as magnetic braking, opposition to motion in generators and the behavior of transformers. Together, these laws allow precise prediction of both the magnitude and direction of induced currents in electromagnetic systems.

What does it mean for a current to be “induced” in a conductor?

It means that the current appears without connecting a battery or any external power source. It happens when a conductor is inside a magnetic field that changes over time. That change “pushes” the electrons and makes them move, creating an electric current. This can occur by moving a magnet near a coil, moving the coil inside the field or changing the strength of the magnetic field. It is the basic principle behind electric generators.

What do Faraday’s Law and Lenz’s Law say in simple terms?

Faraday’s Law says that the faster a magnetic field changes, the stronger the induced current will be. If the change is slow or small, the current will be weak. Lenz’s Law explains the direction of that current: it always flows in a way that opposes the change that created it. If the magnetic field increases, the induced current tries to reduce it; if it decreases, the current tries to maintain it. It is like the circuit’s natural reaction to resist changes.

What is electromagnetic induction used for in everyday life?

Electromagnetic induction is used in many devices. Electric generators convert motion into electricity using this principle. Transformers change voltage levels thanks to induced currents. Electric motors work because induced currents create forces that produce movement. Wireless chargers, magnetic card readers, induction cooktops and magnetic braking systems also rely on induction. It is one of the most important principles in modern technology.