How many milliseconds are in one cycle?

The correct answer reflects the relationship between frequency and time in alternating current (AC) circuits. In an AC system, the frequency is often expressed in hertz (Hz), which indicates the number of cycles per second.

For a frequency of 60 Hz, which is common in the United States, one cycle would thus take 1/60 of a second to complete. To convert this into milliseconds, we multiply by 1000 (since 1 second equals 1000 milliseconds):

1 cycle = (1/60 seconds) × 1000 milliseconds/second = approximately 16.67 milliseconds.

Therefore, it takes around 16.7 milliseconds to complete one full cycle at a frequency of 60 Hz, making this choice accurate. Understanding this concept is essential for substation electricians, as it helps in the proper analysis and management of electrical systems. This knowledge is also critical when working with electrical measurements and settings.