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In a line of sight radio communication, a distance of about 50 km is kept between the transmitting and receiving antennas. If the height of the receiving antenna is 70m, then the minimum height of the transmitting antenna should be - (Radius of the earth = 6.4 × 10⁶ m).

1. 32 m
2. 51 m
3. 40 m
4. 20 m

Correct answer: 32 m

Solution

The minimum height of the transmitting antenna can be calculated using the formula that relates the height of the antennas to the distance between them, considering the curvature of the Earth. Given the height of the receiving antenna and the distance, a height of 32 m for the transmitting antenna ensures that the line of sight is maintained over the 50 km distance.

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