What basic principle does a transformer work on?

• A. Capacitance
• B. Ohm's Law
• C. Mutual Induction
• D. Conductivity

Answer: (C)

A transformer operates on the principle of mutual induction, which is a fundamental concept of electromagnetism. This principle involves the generation of an electromotive force (EMF) in a coil of wire when the magnetic field around it changes. Inside a transformer, there are two coils of wire: the primary coil, which receives the input voltage, and the secondary coil, which delivers the transformed output voltage.

When alternating current flows through the primary coil, it creates a varying magnetic field. This changing magnetic field induces an EMF in the secondary coil according to Faraday's law of electromagnetic induction. The amount of voltage induced in the secondary coil is determined by the turns ratio between the primary and secondary coils, allowing transformers to either increase (step up) or decrease (step down) voltage levels effectively.

This principle is crucial because it allows for the efficient transfer of electrical energy between circuits at different voltage levels, which is essential for power distribution systems.