What is a radio wave?

• A. An electromagnetic wave with frequency characteristics useful for radio transmission.
• B. A sound wave used in air navigation.
• C. A wave used for infrared satellite communication.
• D. A mechanical wave produced by propeller motion.

Answer: (A)

Radio waves are a type of electromagnetic wave defined by frequencies that are suitable for radio transmission. They carry energy through oscillating electric and magnetic fields and can travel through space, including through vacuum, which enables wireless communication. This is what sets them apart from sound waves, which are mechanical pressure waves that require a medium like air; infrared waves, while also electromagnetic, occupy a different part of the spectrum and aren’t used as radio waves; and a wave produced by propeller motion is a mechanical disturbance, not an electromagnetic wave. So the description that emphasizes an electromagnetic wave with frequencies used for radio transmission best captures what a radio wave is.