The line of sight distance for two antennas of height 100 m and 400 m above earth surface is approximtely. (Given $R = 6400 km, \sqrt{20}=4.5$)

108 km

The correct answer is Option (3) → 108 km

To calculate the line of sight distance (d) between two antennaas -

$d=\sqrt{2h_1R}+\sqrt{2h_2R}$

Given,

$h_1=100m$

$h_2=400m$

$R=6.4×10^6m$

$∴d=\sqrt{2×100×6.4×10^6}+\sqrt{2×400×6.4×10^6}$

$≃108km$