A transmitting antenna at the top of a tower has a height 18 m and the height of the receiving antenna is 32 m. What is the maximum distance between them for satisfactory communication in line-of-sight mode? Given radius of earth is $6.4 × 10^6 m$.

35.4 km

The correct answer is Option (3) → 35.4 km

Maximum distance for LOS communication is -

$d=\sqrt{2Rh_t}+\sqrt{2Rh_r}$

$h_t=18m$ [given]

$h_r=32m$ [given]

$∴d\sqrt{2×(6.4×10^6)×18}+\sqrt{2×(6.4×10^6)×32}$

$=20,240m+15,174m$

$=35.4km$