Question

Television signals from transmission towers are restricted to a limited area because

• A. the signals become weak with distance
• B. there is inteference from other signals
• C. of the Earth's curvature
• D. the atmosphere absorbs the signals

Answer 1

The Correct Option is C

Step 1: Understand the question
The question asks why television signals from transmission towers cannot reach beyond a limited area and are restricted in range.

Step 2: Nature of TV signals
Television signals are electromagnetic waves, specifically radio waves in the Very High Frequency (VHF) and Ultra High Frequency (UHF) ranges. These signals generally travel in straight lines and are known as line-of-sight waves.

Step 3: Limitation of range
Since TV signals travel in straight lines, they cannot bend around obstacles significantly (unlike long-wave radio signals which can diffract). The biggest natural obstacle is the curvature of the Earth. As the Earth curves away, the line-of-sight path is cut off, restricting the coverage area of the signals. The higher the transmission tower, the farther the line-of-sight distance, but it still remains limited by Earth’s curvature.

Step 4: Final justification
Therefore, the restriction of TV signal coverage to a limited area is not due to weak transmission power or atmospheric absorption, but mainly because straight-line signals are blocked by the Earth’s curvature.

Final Answer: The correct option is (C) of the Earth’s curvature.