What physical principle underlies the operation of a transformer?

The operation of a transformer is based on the principle of electromagnetic induction. This principle states that a changing magnetic field within a coil of wire induces an electromotive force (EMF) or voltage in that wire. In a transformer, when an alternating current flows through the primary coil, it creates a changing magnetic field. This magnetic field then passes through the secondary coil, inducing a voltage across it because the magnetic field is changing.

Transformers are designed to change the voltage of an alternating current. The number of loops in the primary coil compared to the secondary coil determines whether the voltage is stepped up or stepped down. This relationship is governed by electromagnetic induction, illustrating how changes in magnetic fields can produce electrical energy.

The other principles mentioned, such as thermodynamics, Ohm's law, and Newton's law, do not directly relate to how transformers operate. Thermodynamics deals with heat and energy transfer, Ohm's law relates to current, voltage, and resistance in electrical circuits, and Newton's law refers to motion and forces. None of these principles encompass the mechanism by which transformers function in transferring energy between coils through magnetic fields.