Which type of electromagnetic wave is primarily used for communication?

• A. Radio waves
• B. Microwaves
• C. Infrared light
• D. Ultraviolet light

Answer: (A)

Radio waves are used for communication because their long wavelengths travel well through the atmosphere and across long distances, and antennas can efficiently transmit and receive them. This makes them ideal for a wide range of systems—from radio broadcasting to mobile networks and satellite links—without requiring strict line-of-sight. Microwaves also carry signals and are used in certain high-capacity links, but they demand more precise alignment and often line-of-sight, which limits their versatility. Infrared light can carry information too, but it doesn’t pass through walls or weather well, so it’s mainly for short-range, line-of-sight links. Ultraviolet light isn’t practical for everyday communications because it is highly energetic, absorbed by the atmosphere, and poses safety risks. So the type most suited for general communication is radio waves.