What is the role of a transformer in an electrical system?

The role of a transformer in an electrical system is fundamentally about changing voltage levels, as indicated by the correct answer. Transformers are electrical devices used to either step up (increase) or step down (decrease) voltage in a power system. This ability to modify voltage is essential for efficient power transmission and distribution. High voltages are used for long-distance transmission to minimize energy loss due to resistance in the wires, while lower voltages are used for safe distribution throughout homes and businesses.

Transformers operate based on the principle of electromagnetic induction, where an alternating current in one coil creates a magnetic field that induces a voltage in another coil. By adjusting the ratio of the number of windings in the primary and secondary coils, a transformer can effectively change the voltage level that is delivered to the load.

While measuring electrical resistance, storing electrical energy, and generating electricity from renewable sources are important functions within electrical and power systems, they do not pertain to the function of a transformer specifically. Hence, the correct answer highlights the essential and specific role that transformers play in managing voltage levels.