ARRL Technician Practice Exam

What are the two components of a radio wave?

1. Electric and magnetic fields

2. Sound and light waves

3. Temperature and pressure

4. Frequency and amplitude

The correct answer is: Electric and magnetic fields

A radio wave consists of both electric and magnetic fields that are perpendicular to each other and to the direction of wave propagation. This interplay between the electric and magnetic components is fundamental to the nature of electromagnetic waves, which include radio waves. When a charged particle, such as an electron, is accelerated, it creates a changing electric field. This changing electric field, in turn, generates a magnetic field. The two fields continually induce each other as the wave propagates through space. In contrast, sound and light waves represent different phenomena. Sound waves are mechanical waves requiring a medium to travel, while light waves, although they are electromagnetic in nature, do not refer specifically to the characteristics of radio waves. Temperature and pressure are physical properties that can affect radio wave transmission but are not themselves components of a radio wave. Frequency and amplitude describe aspects of the wave, such as its characteristics and energy, rather than being physical components of the wave itself.