What is the main frequency used by Wi-Fi 802.11b technology?

Wi-Fi 802.11b operates primarily on the 2.4 GHz frequency band. This frequency was chosen because it allows for a good balance between range and data rates, making it suitable for typical home and office environments. The 2.4 GHz band can cover larger distances compared to higher frequency bands, such as 5.0 GHz, and is capable of penetrating walls and other obstacles more effectively.

While other options present frequencies used by various wireless technologies, they do not align with the standard for 802.11b. For example, 5.0 GHz is associated with other Wi-Fi standards, such as 802.11a and 802.11n, but not 802.11b. The 900 MHz and 1.5 GHz frequencies are not standard frequencies for Wi-Fi networking and are used for different communication technologies or applications. Therefore, the 2.4 GHz band is indeed the correct and key frequency for 802.11b technology.