How is frequency defined in electrical systems?

Frequency in electrical systems is defined as the number of cycles of alternating current (AC) that occur in one second, measured in hertz (Hz). This means that if a waveform completes one full cycle—one oscillation from zero to maximum value and back to zero again—every second, it has a frequency of 1 Hz. When discussing AC systems, understanding frequency is crucial as it affects the performance of electrical devices, synchronization of signals, and the behavior of circuits.

For example, in a typical power supply, the frequency is often set at 50 Hz or 60 Hz, indicating that the current alternates direction 50 or 60 times per second. This periodic nature is vital for the proper operation of many electrical devices that rely on a stable frequency to function correctly.

The other options pertain to different electrical concepts: the speed of current flow relates to the drift velocity of charge carriers, voltage refers to the electric potential difference that drives current through a circuit, and total resistance is a measure of how much a circuit opposes the flow of electric current. These concepts are important, but they do not define frequency within electrical systems.