Option 1: Infrared radiations are electromagnetic waves with longer wavelengths than visible light. They are commonly used in devices such as remote controls and heaters, but they are not used for satellite communication.
Option 2: Ultraviolet radiations have shorter wavelengths than visible light. They are often used in applications such as sterilization and sunscreen, but they are not used for satellite communication.
Option 3: The correct answer. Radio waves are electromagnetic waves with the longest wavelengths. They are used for various communication systems, including satellite communication.
Option 4: Visible light is the portion of the electromagnetic spectrum that can be detected by the human eye. While visible light is used for various applications, it is not the primary choice for satellite communication.
In conclusion, the correct option for the electromagnetic waves used in satellite communication is option 3, radio waves.