Deep Dive: T5A12
The correct answer is D: Frequency. The term that describes the number of times per second that an alternating current makes a complete cycle is frequency. Frequency is measured in hertz (Hz), where 1 Hz = 1 cycle per second. In an AC cycle, the current goes from zero, to maximum positive, back to zero, to maximum negative, and back to zero - that's one complete cycle. Frequency tells you how many of these complete cycles happen per second. For example, 60 Hz AC power completes 60 cycles per second. Higher frequency means more cycles per second. Frequency is fundamental to radio - radio signals are high-frequency AC currents, and the frequency determines which band you're operating on.
Why Other Answers Are Wrong
Option A: Incorrect. Pulse rate refers to pulses in digital signals, not the number of AC cycles per second. Option B: Incorrect. Speed typically refers to velocity (distance per time), not the number of cycles per second. Option C: Incorrect. Wavelength is the distance a wave travels in one cycle, not the number of cycles per second.
Exam Tip
Cycles per second = Frequency. Remember: Frequency (hertz) describes how many complete AC cycles occur per second. 1 Hz = 1 cycle per second.
Memory Aid
**C**ycles **P**er **S**econd = **F**requency (think 'CPS = F' = Cycles Per Second = Frequency)
Real-World Example
Your household AC power operates at 60 Hz. This means the current completes 60 full cycles every second - going from zero to positive maximum, back to zero, to negative maximum, and back to zero, 60 times per second. The frequency tells you how fast the AC is oscillating. In radio, frequencies are much higher - 146.52 MHz means 146,520,000 cycles per second.
Source & Coverage
Question Pool: 2022-2026 Question Pool
Subelement: T5A
Reference: FCC Part 97.3
Key Concepts
Verified Content
Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T5A topic.