Which of the following statements best characterizes a ground wave?

Which of the following statements best characterizes a ground wave?

• A. It follows the curvature of the Earth and travels long distances.
• B. It travels in a straight line through space.
• C. It relies on line-of-sight only.
• D. It is always unaffected by absorption.

Answer: (A)

Ground waves travel along the Earth’s surface, hugging the terrain as they propagate. This happens because the electromagnetic field interacts with the conducting ground and atmosphere, causing diffraction and guided behavior that lets the signal bend with the curvature of the planet and reach receivers beyond the visual horizon. That’s why low-frequency transmissions—like many AM broadcasts—can be received far away, even when there’s no clear line of sight. The idea that a ground wave travels in a straight line through space, or relies only on line of sight, or is completely immune to absorption, doesn’t fit this behavior. Ground waves do experience attenuation due to ground conductivity, moisture, terrain, and frequency, which shapes how far they travel.

Ground waves travel along the Earth’s surface, hugging the terrain as they propagate. This happens because the electromagnetic field interacts with the conducting ground and atmosphere, causing diffraction and guided behavior that lets the signal bend with the curvature of the planet and reach receivers beyond the visual horizon. That’s why low-frequency transmissions—like many AM broadcasts—can be received far away, even when there’s no clear line of sight. The idea that a ground wave travels in a straight line through space, or relies only on line of sight, or is completely immune to absorption, doesn’t fit this behavior. Ground waves do experience attenuation due to ground conductivity, moisture, terrain, and frequency, which shapes how far they travel.