Which of the following is an example of RF energy?

• A. The energy stored in a capacitor
• B. The energy beaming from a transmitting antenna
• C. The energy from a battery
• D. The energy from a magnet

Answer: (D)

RF energy is energy carried by radio waves—the electromagnetic waves at radio frequencies that travel through space. When a transmitter feeds an antenna, the antenna converts electrical power into these traveling waves, radiating energy into the air as RF energy.

The other examples describe energy stored or static: a capacitor holds electric energy in the electric field between its plates, a battery provides chemical/electrical energy, and a magnet stores magnetic field energy. These are not inherently energy traveling as radio waves.

So the example that represents RF energy is energy beaming from a transmitting antenna, since it involves radiating electromagnetic waves at radio frequencies.