Characteristics of alternating currents — FAQ

AC is favoured for mains power primarily because its voltage can be easily stepped up or down using transformers. This allows for high-voltage, low-current transmission over long distances, which significantly reduces power loss ($P=I^2R$) in the cables.

Frequency ($f$) is the number of complete cycles per second, measured in Hertz (Hz). Angular frequency ($\omega$) describes the rate of change of the phase angle of the waveform, measured in radians per second (rad s⁻¹). They are related by $\omega = 2\pi f$, where $2\pi$ is the number of radians in one full cycle.

No, this specific relationship ($V_{rms} = V_{peak}/\sqrt{2}$) is only valid for sinusoidal alternating currents. For other waveform shapes (e.g., square waves, triangular waves), the relationship between RMS and peak values is different.