What did Michael Faraday demonstrate in August 1831 using two coils of wire and an iron ring?

Answer

The principle of electromagnetic induction

Faraday proved that a changing magnetic field could induce an electric current in a nearby conductor. By wrapping two coils around an iron ring and observing a current in the second coil when power was applied to the first, he established the foundational physics that allows transformers to transfer energy between electrically isolated circuits.

What did Michael Faraday demonstrate in August 1831 using two coils of wire and an iron ring?

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History of Power Transformers - YouTube

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