Michael Faraday, Inventor of Electromagnetic Induction
Second, magnetic fields that vary with time can produce (induce) electric fields in the form of electric current. This symptom is known as the symptom of electromagnetic induction. The concept of electromagnetic induction was discovered experimentally by Michael Faraday and formulated in full by Joseph Henry. The law of electromagnetic induction itself came to be known as Faraday-Henry's Law.
Of the two basic principles of magnetic electricity above and by considering the concept of symmetry that applies in natural law, James Clerk Maxwell proposed a proposal. The proposal put forward by Maxwell, namely that if a magnetic field that changes with time can produce an electric field then the opposite may be possible. Thus Maxwell proposes that an electric field that changes with time can produce (induce) a magnetic field. Maxwell's proposal then becomes the third law that connects electricity and magnetism.
James Clerk Maxwell laying the groundwork for the theory of electromagnetic waves
So, the third principle is that an electric field that changes with time can produce a magnetic field. This third principle proposed by Maxwell basically is the development of Ampere's legal formulation. Therefore, this principle is known as Ampere-Maxwell's Law.
Of the three basic principles of electricity and magnetism above, Maxwell sees an archetype. A magnetic field that changes with time can generate an electric field that also changes with time, and an electric field that changes with time can also produce a magnetic field.
If this process takes place continuously it will produce a magnetic field and an electric field continuously. If the magnetic and electric fields simultaneously propagate (spread) in space in all directions then this is a symptom of waves. Such waves are called electromagnetic waves because they consist of electric and magnetic fields that propagate in space.
At first the electromagnetic waves were still in the form of a prediction from Maxwell, whose intuition was able to see the basic pattern in electricity and magnetism, as discussed above. This fact makes J C Maxwell considered the inventor and formulator of the basics of electromagnetic waves.
Maxwell's theory of electricity and magnetism
Maxwell's theory of electricity and magnetism predicts the existence of electromgnetic waves
Some rules about magnetism and electricity that support the development of the concept of electromagnetic waves include:
Coulomb's Law states: "A static electric charge can produce an electric field."
The Biot & Savart Law states: "The flow of an electric charge (electric current) can produce a magnetic field".
Faraday's Law states: "Changes in magnetic fields can produce electric fields".
Based on Faraday's Law, Maxwell put forward the following hypothesis: "Changes in the electric field can cause magnetic fields". This hypothesis has been tested and is called the Maxwell Theory.