Which pair correctly matches North America with rest of the world in terms of electrical frequency?

• A. 60 Hz in North America and 50 Hz elsewhere
• B. 50 Hz in North America and 60 Hz elsewhere
• C. 60 Hz everywhere
• D. 50 Hz everywhere

Answer: (A)

Electrical systems are built to run at a specific AC frequency, and North America uses 60 Hz while most of the world uses 50 Hz. This difference stems from historical choices and affects how motors, transformers, and timing devices are designed to operate in a region. The pairing that North America is 60 Hz and elsewhere is 50 Hz matches real-world practice, which is why it’s the correct choice. The other options would imply North America uses 50 Hz or that the entire world uses the same frequency, which isn’t how power grids are set up.