What physical law allows transformation of voltage and current using a transformer?

The transformation of voltage and current in a transformer is governed by the principle of electromagnetic induction. This physical law describes how a changing magnetic field can induce an electric current in a conductor. In a transformer, when alternating current flows through the primary coil, it creates a varying magnetic field, which is then linked to the secondary coil. This changing magnetic field induces a voltage in the secondary coil based on the turns ratio of the coils, which determines how voltage and current levels are transformed.

Electromagnetic induction is crucial for the functional operation of transformers, allowing them to step up or step down voltages depending on the number of turns in the primary and secondary coils. This process is fundamental in power systems for efficiently transmitting electricity over long distances, as it allows for the adjustment of voltage levels to reduce losses.

Other options do not relate to the function of transformers in this context. Newton's laws pertain to motion, Ohm's law relates to the relationship between voltage, current, and resistance in a circuit, and Faraday's law of electrolysis focuses on the chemical reaction in electrolytic cells rather than electrical transformation through magnetic fields.