The standard frequency of AC power supply in most countries around the world is 50 Hz or 60 Hz. The frequency used depends on the region and the historical choices made when establishing electrical systems.
In many countries, including Europe, Africa, Asia, and Australia, the standard frequency is 50 Hz.
In North America and some parts of South America, the standard frequency is 60 Hz.
These frequencies are important because they determine the rate at which the alternating current changes direction (cycles per second), and they impact the design and operation of electrical devices and systems.