Technician: Components of a Radio Wave

What are the two components of a radio wave? [T3B03]

A. AC and DC
B. Voltage and current
C. Electric and magnetic fields
D. Ionizing and non-ionizing radiation

This is a “definition” type of question, one that if I remember correctly was posed to us on day one of my college Electromagnetics class.

A “radio wave” is just an electromagnetic wave that falls within the “radio” portion of the spectrum.  Fundamentally, there is no difference between a radio signal, and a beam of light.  They’re the same thing, only the light beam is at a much, much higher frequency than the radio wave.  Light wavelengths are measured in nanometers (think billionths) of a meter, where radio wavelenghts are measured anywhere from millimeters (microwave) up to hundreds of meters (i.e. AM broadcast.)

But I’m getting off topic.  An EM wave is composed of an electric field component, and a magnetic field component (makes sense, right? electro-magnetic waves!)  Mathematically, and physically speaking, they exist “orthogonally” or at right angles to each other.  See the pic above.

The answer, therefore, is C. Electric and magnetic fields. 

Leave a Comment