What is the standard frequency for AC electric power supplied by utility companies in the US?

What is the standard frequency for AC electric power supplied by utility companies in the US?

• A. 50 cycles per second (50 Hz)
• B. 60 cycles per second (60 Hz)
• C. 400 cycles per second (400 Hz)
• D. 120 cycles per second (120 Hz)

Answer: (B)

Frequency is how fast the AC voltage cycles each second. In the United States, the standard utility-supplied AC frequency is 60 Hz, meaning the voltage completes 60 full cycles every second. This convention keeps electrical devices, motors, and transformers operating predictably with the grid. Other regions use 50 Hz, so equipment might be designed for that cadence; 400 Hz is used in some aircraft systems to reduce weight, not for the general power grid; 120 Hz would be the ripple frequency you'd see if 60 Hz AC is rectified to DC, not the actual AC supply frequency. So the correct standard for US utility power is 60 Hz.

Frequency is how fast the AC voltage cycles each second. In the United States, the standard utility-supplied AC frequency is 60 Hz, meaning the voltage completes 60 full cycles every second. This convention keeps electrical devices, motors, and transformers operating predictably with the grid. Other regions use 50 Hz, so equipment might be designed for that cadence; 400 Hz is used in some aircraft systems to reduce weight, not for the general power grid; 120 Hz would be the ripple frequency you'd see if 60 Hz AC is rectified to DC, not the actual AC supply frequency. So the correct standard for US utility power is 60 Hz.