What are ground waves ?

Explanation

**Step-by-Step Solution:**

1. **Definition of Ground Waves**: Ground waves are a type of electromagnetic wave, specifically radio waves, that travel along the surface of the Earth.

2. **Transmission Mechanism**: These waves are transmitted from a transmitting antenna and received by a receiving antenna. The key characteristic of ground waves is that they travel directly along the Earth's surface.

3. **Propagation Characteristics**: Ground waves follow the contour of the Earth, which means they can bend around obstacles and follow the curvature of the Earth, allowing them to propagate over long distances, especially at lower frequencies.

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