What happens when the coil of a relay is energized?

When the coil of a relay is energized, it creates an electromagnetic field that activates the relay. This activation typically results in the movement of a switch within the relay, allowing current to flow to a connected circuit. The relay serves as an electrically operated switch, where energizing the coil causes the mechanical components inside to either open or close the contacts of the relay.

Activating the relay is the main purpose of energizing the coil, as the controlled switch operation can then manage larger loads or isolate circuits, making relays invaluable in various applications. Other options discuss changes in electrical measurements or physical phenomena that do not directly reflect what occurs in this specific scenario of coil energization.