Television signal on earth cannot be recevied at distances greater than `100 km` from the transmission station. The reasion behind this is that

Options

A. the receiver antenna is unable to detect the signal at a distance greater then 100 km
B. the TV programme consists of both audio and video signals
C. The TV signals are less powerful than radio signals.
D. the surface of earth is curved like a sphere

Answer

To solve the question regarding why television signals on Earth cannot be received at distances greater than 100 km from the transmission station, we can analyze the situation step by step.

### Step-by-Step Solution:

1. **Understanding the Transmission of Signals**:
- Television signals are transmitted from antennas located at transmission stations. These signals travel in straight lines from the antenna.

2. **Distance Limitation**:
- The question states that television signals cannot be received beyond 100 km. This indicates that there is a limitation to how far these signals can effectively travel.

3. **Role of the Earth's Curvature**:
- The Earth is not flat; it has a curved surface. As the distance from the transmission station increases, the curvature of the Earth causes the signals to eventually "drop off" or become too weak to be detected.

4. **Signal Loss**:
- Beyond a certain distance (in this case, 100 km), the signals emitted from the antenna can no longer reach the receiver because they are lost into space due to the curvature of the Earth. This phenomenon is similar to how objects can disappear from view as they move beyond the horizon.

5. **Conclusion**:
- The primary reason that television signals cannot be received beyond 100 km from the transmission station is due to the curvature of the Earth's surface. Therefore, the correct answer is that the surface of the Earth is curved like a sphere.

### Final Answer:
The reason television signals on Earth cannot be received at distances greater than 100 km from the transmission station is that the surface of the Earth is curved like a sphere.

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