Problem 16CQ

Why do voltage, current, and power go through zero 120 times per second for 60-Hz AC electricity?

Solution 16CQ

Frequency is defined as the number of cycle per second. Voltage, current and power generally has standard sine waves.

One sine wave crosses zero twice to complete one cycle. Frequency is 60 Hz means 60 cycles per second. Hence, for 60 Hz it will cross zero 120 times per second.