The intensity of the ground waves decrease with increase of distance due to

Options

A. Interference
B. Diffraction
C. Polarization
D. Due to unknown reason

Answer

### Step-by-Step Solution:

1. **Understanding Ground Waves**: Ground waves are electromagnetic waves that travel along the surface of the Earth. They are used in communication systems, particularly for low-frequency transmissions.

2. **Observation of Intensity Decrease**: It is observed that the intensity of ground waves decreases as the distance from the source increases. This means that the energy carried by the wave diminishes over distance.

3. **Possible Reasons for Intensity Decrease**: The question provides four options for the reason behind this decrease in intensity:
- Interference
- Diffraction
- Polarization
- Unknown reason

4. **Analyzing the Options**:
- **Interference**: This occurs when two waves meet and can lead to constructive or destructive interference. However, it does not primarily explain the consistent decrease in intensity with distance.
- **Diffraction**: This is the bending of waves around obstacles and openings. Ground waves can bend as they propagate along the Earth's surface. This bending can lead to a loss of energy as the wave interacts with the surface.
- **Polarization**: This refers to the orientation of the wave's electric field. While it affects the propagation of waves, it does not directly explain the decrease in intensity with distance.
- **Unknown Reason**: This option suggests that the decrease in intensity has no known cause, which is not accurate as physical principles can explain it.

5. **Conclusion**: The most suitable explanation for the decrease in intensity of ground waves with distance is **diffraction**. As ground waves travel, they bend and interact with the Earth's surface, leading to energy absorption and a resultant decrease in intensity.

### Final Answer:
The intensity of the ground waves decreases with increase of distance due to **diffraction**.

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