Michael Faraday’s Laws of Electromagnetic Induction
Faraday’s Laws of Electromagnetic Induction were formulated by the British scientist Michael Faraday in the early 19th century. Faraday conducted groundbreaking experiments that laid the foundation for our understanding of electromagnetism and the relationship between electricity and magnetism.
The story of Faraday’s Laws began in the 1820s when Faraday began to study the work of earlier scientists, such as Hans Christian Oersted, who discovered that an electric current could create a magnetic field. Inspired by Oersted’s findings, Faraday sought to explore the reciprocal relationship—whether a magnetic field could induce an electric current.
In 1831, Faraday conducted a pivotal experiment known as the “magnetic induction experiment.” He used a coil of wire connected to a galvanometer (a device to detect electric currents) and moved a permanent magnet inside the coil. He observed that whenever there was relative motion between the magnet and the coil, a momentary current would flow through the wire. When he moved the magnet away or toward the coil, the galvanometer indicated that a current was induced, but the direction of the current depended on the direction of the motion (approaching or receding). From this experiment, Faraday formulated his first law of electromagnetic induction.
Faraday’s investigations didn’t stop there. In his subsequent experiments, he made another significant discovery. In 1831, he wrapped two separate coils of wire around an iron ring and connected one of the coils to a battery. When he passed a current through this coil, he noticed that it produced a magnetic field, which, in turn, induced a current in the other coil—despite the lack of direct electrical connection between them. Through this experiment, Faraday formulated his second law of electromagnetic induction.
What is called Electromagnetic Induction?
Electromagnetic induction refers to the interaction between a magnetic field and an electric circuit, resulting in the generation of an electromotive force (EMF).
Faraday’s First Law of Electromagnetic Induction
Whenever there is a change in the magnetic flux linking with a conductor or coil, it results in the induction of an electromotive force (EMF) in the conductor or coil. This phenomenon is known as induced EMF, and it leads to the circulation of current in the circuit, known as induced current if the circuit is closed.
Faraday’s Second Law of Electromagnetic Induction
The magnitude of the induced EMF depends on the rate of change of flux that is linked with the coil.