Question T5A12
From subelement T5 - T5A
What describes the number of times per second that an alternating current makes a complete cycle?
Why is this correct?
Frequency describes the number of complete AC cycles per second. A complete cycle includes current flowing positive, returning to zero, flowing negative, and returning to zero again. This repetition rate is measured in Hertz (Hz). Pulse rate refers to discrete pulses, speed relates to velocity, and wavelength is the physical distance a wave travels during one cycle - none describe the time-based repetition of AC cycles.
Memory tip
Remember the pattern: frequency always answers 'how many times per second' for any repeating phenomenon in electronics. Whether it's AC power (60 Hz), radio waves (MHz), or audio signals (kHz), frequency quantifies repetition rate over time.
Learn more
Household AC frequency is 60 Hz, meaning 60 complete cycles per second. Amateur radio operates across frequency privileges from 1.8 MHz to 1.3 GHz and beyond. Understanding frequency helps you grasp why different amateur bands have different propagation characteristics - lower frequencies (longer wavelengths) tend to travel farther but require larger antennas, while higher frequencies offer more bandwidth but typically shorter range.
Think about it
Why do you think amateur radio allocates different frequency privileges to different license classes, and how does this relate to the fundamental concept of frequency as cycles per second?