_______ are used for cellular phone, satellite, and wireless LAN communications.a.Microwavesb.Infrared wavesc.None of thesed.Radio waves

To determine which type of electromagnetic wave is used for cellular phone, satellite, and wireless LAN communications, we need to analyze the options provided.

1. Microwaves: These are high-frequency electromagnetic waves that are utilized in various forms of communication, including satellite and cellular networks. Microwaves can carry significant amounts of data over long distances, making them suitable for these applications.

2. Infrared waves: Generally used for short-range communication, infrared waves are not typically suited for cellular phones or satellite communications, although they can be found in remote controls and some wireless device connections.

3. Radio waves: These are the most common forms of electromagnetic radiation used in all forms of broadcast communication, including cellular phones, televisions, and radio broadcasts. Radio waves can propagate over long distances and are favored for their ability to penetrate various atmospheres.

4. None of these: This option suggests that none of the provided solutions are correct. However, we have identified that both microwaves and radio waves are indeed used for communications.

Final Answer:

The correct answer is a. Microwaves and d. Radio waves are both utilized for cellular phone, satellite, and wireless LAN communications.