Faraday's Law describes what phenomenon?

• A. An electric field is induced in any region of space where a magnetic field changes with time
• B. A magnetic field is induced by a changing electric field
• C. The speed of light depends on the magnetic field
• D. An electric field is induced only if there is a conductor present

Answer: (A)

A changing magnetic field creates an electric field in space. Faraday’s law, written in its field form as curl E = -∂B/∂t, means that whenever the magnetic field varies with time, the electric field forms circulating lines around the region of change. This induced electric field exists even in empty space, and it’s the mechanism behind electromagnetic induction used by transformers, generators, and inductors.

That’s why the correct choice describes an electric field being induced wherever the magnetic field changes with time. It’s not about a changing electric field creating a magnetic field (that is a related part of Maxwell’s equations but a different relation). It doesn’t say the speed of light depends on the magnetic field, and the induction of E does not require a conductor to be present—conductors merely allow current to flow in response to the induced field.