Question

The radius of the Earth is 6400 km. If the height of an antenna is 500 m, then its range is

• A. 800 km
• B. 100 km
• C. 80 km
• D. 10 km

Answer 1

Answer: (C)

80 km

Answer 2

$d = \sqrt {2h_T R} = \sqrt{2 \times 500\times 6400000}$
$= \sqrt{10^3 \times 64 \times 10^5}$
$= 8 \times 10^4 =80\, km$