ARRL Technician Practice Exam

What property of a radio wave is used to describe its polarization?

1. The orientation of the electric field

2. The frequency of the wave

3. The amplitude of the wave

4. The wavelength of the wave

The correct answer is: The orientation of the electric field

The property of a radio wave that describes its polarization is determined by the orientation of the electric field. In electromagnetic waves, including radio waves, there are both electric and magnetic fields that oscillate perpendicular to one another. Polarization specifically refers to the direction in which the electric field oscillates. For instance, if the electric field oscillates in a vertical orientation, the wave is considered vertically polarized. Conversely, if it oscillates horizontally, it is horizontally polarized. This property is crucial in radio communication as it affects how antennas receive and transmit signals; antennas designed to work with a specific polarization will perform better if the wave's polarization matches that of the antenna. The other options—frequency, amplitude, and wavelength—do not pertain to polarization. Frequency relates to how often the radio wave oscillates per second, amplitude refers to the strength or power of the wave, and wavelength is the physical distance between successive peaks of the wave. These properties are important in their own right but do not define the polarization of a radio wave.