The energy transfer between windings in a transformer occurs without direct electrical contact, via a magnetic field. This describes which principle?

• A. Induction
• B. Conduction
• C. Polarization
• D. Diffusion

Answer: (A)

Electromagnetic induction is at work here. A changing current in the primary winding creates a time-varying magnetic field in the core, which links to the secondary winding. This changing magnetic flux induces a voltage in the secondary according to Faraday’s law, allowing energy to transfer through the magnetic field without any direct electrical contact. Conduction would require a physical path between windings, polarization involves dipole alignment in materials, and diffusion is about particles spreading—none of those explain energy transfer via a magnetic field, so induction is the correct principle.