What type of radio wave reaches a receiver directly from a transmitter without bouncing off other surfaces?

The correct answer refers to a type of radio wave that travels directly from the transmitter to the receiver without any reflection off surfaces such as the ground or ionosphere. This direct path is typically characteristic of ground waves, which follow the curvature of the Earth and can propagate over a significant distance.

Ground waves are used primarily in lower-frequency radio communications, such as AM radio broadcasting, where they can travel along the surface of the Earth. This ability allows ground waves to maintain consistent communication even when line-of-sight may not be achievable due to obstacles or distance.

In contrast, sky waves involve the reflection of radio waves off the ionosphere, a phenomenon used for long-distance communication, while direct waves would imply a specific line-of-sight transmission not necessarily bound to the Earth’s surface. Reflective waves typically concern waves bouncing off surfaces, which does not apply to the question asking for direct transmission. Thus, the definition of ground wave aligns with the concept of direct reception without intermediate reflections.