What frequency do Bluetooth devices operate at?

Bluetooth devices operate at a frequency of 2.4 GHz. This frequency band is part of the ISM (Industrial, Scientific, and Medical) radio bands, which are designated for unlicensed use globally. The choice of 2.4 GHz allows Bluetooth technology to provide a good balance between range and data transfer speed while minimizing interference with other wireless technologies, as many devices such as Wi-Fi and microwave ovens also operate in the same band.

The 2.4 GHz frequency allows Bluetooth to establish connections over short distances, typically up to about 100 meters, depending on the class of the Bluetooth device. By using frequency-hopping spread spectrum technology, Bluetooth can avoid interference from other devices operating in the same 2.4 GHz range, thereby maintaining reliable communication.

Other frequencies provided in the options are not utilized by standard Bluetooth technology, making 2.4 GHz the correct and relevant answer for Bluetooth device operation.