Understanding the birth of Electricity (Electromagnetic Induction)

Electromagnetic or magnetic induction is the production of an electromotive force (i.e., voltage) across an electrical conductor in a changing magnetic field.

Michael Faraday is generally credited with the discovery of induction in 1831, and James Clerk Maxwell mathematically described it as Faraday’s law of induction. Lenz’s law describes the direction of the induced field. Faraday’s law was later generalized to become the Maxwell–Faraday equation, one of the four Maxwell equations in his theory of electromagnetism.

What does the Electromagnetic Induction Law Say & How does it happen?

The law says that, when ever there is a change in magnetic field (The inherent effect of a magnet, imagine an invisible thing which leads to the capability of a magnet to attract or repel things) near a piece of conductor like a wire, an electric potential (Voltage) gets developed. You can simply imagine that the moving magnetic field pushes the electrons present inside the conductor and they align and drift leading to the induction of voltage/potential.

Note that the law says Change in Magnetic Field. Its important to stress upon the word “change”. Intuitively also it appears that if there is no change then there should be no movement of electrons. Now in order to induce voltage you can either move the magnet closer or farther to the conductor or can move the conductor towards or away from a magnet, either way there can be change and this is precisely how electricity is generated by a generator and even this is the reason how a motor rotates which we will shortly touch upon.

For the sake of better understanding the following animation will drive home the point.

Can Electricity Cause Magnetism?

What we just learned is how magnetism can give birth to Electricity… if we coin a term for that then may be Magnetoelectrism sounds right!… what about the other way around, can Electricity cause magnetism, of course yes! Lets see how.

Magnetism is a behavior or property due to a certain alignment of charged particles inside objects. We just saw above that magnetism has the ability to push charged particles (Electrons) in certain direction which causes electricity, in the similar fashion, if charged particles are somehow moving in a direction this itself causes magnetism due to the movement in unison. That’s precisely how electromagnets are made. If you look inside an electromagnet, its a coil of wire and each turn adds to another turn and strengthens the effects of the unison movement of charges inside the wire, the more the number of turns the more will be the strength of magnetism.

Magnetism also has a property that it tries to confine or concentrate towards an object which provides a nice and low resistance path. Think of it like a road with less traffic. Every object has different ability to accommodate magnetic fields and that ability is known as permeability. Higher the permeability, higher will be the ability of the object to accommodate the magnetic fields and  this ability is inherited by the objects because of their electronic structures and the way electrons are aligned inside their atoms. The most famous and widely used object for this is Iron. This is the precise reason why inside the coil of an electromagnet, like the one in your doorbell and in any transformer or in a fan there is an iron bar inside the coil. Its there to accommodate and provide a good path to the magnetism generated by the electricity in the coil.

Now we understood that, Electricity can cause magnetism and magnetism can cause electricity and hence we understood the fundamentals of Electromagnetism.