Consider the following:

1. Bluetooth device
2. Cordless phone
3. Microwave oven
4. Wi-Fi device

Which of the above can operate between 2.4 and 2.5 GHz range of radio frequency band?

1. 1 and 2 only
2. 3 and 4 only
3. 1, 2 and 4 only
4. 1, 2, 3 and 4

Explanation

Option (d) is correct

• The frequency band from 2.4 to 2.5 GHz is part of the Industrial, Scientific and Medical radio band. This band is licence-free and widely used for short-range wireless communication and heating applications. Bluetooth devices operate in the 2.4 GHz band as defined by IEEE 802.15 standards. Cordless phones commonly operate in the same frequency range. Microwave ovens use electromagnetic waves at approximately 2.45 GHz to heat food by exciting water molecules. Wi-Fi devices based on the IEEE 802.11b, g, and n standards also operate in the 2.4 GHz band. The lower 2.4 GHz band offers longer range at lower data rates. Therefore, all four listed devices can operate within this frequency range.

Answer: (d) 1, 2, 3 and 4