What frequency of electricity does North America use?

• A. 50 hertz
• B. 60 hertz
• C. 120 hertz
• D. 200 hertz

Answer: (B)

Frequency is how many times the alternating current reverses direction each second. In North America, the standard utility frequency is 60 cycles per second, or 60 hertz. This standard shapes the design of motors, transformers, and most household electronics that expect a 60 Hz supply. The other numbers correspond to frequencies used in other regions or contexts: 50 hertz is common overseas, while 120 hertz and 200 hertz are not standard mains frequencies in North America.