Q 12-08-170JEE MainJEE Main 2021 (26 Aug, Shift 2)Easy
A transmitting antenna at top of a tower has a height of $50$ m, and the height of receiving antenna is, $80$ m. What is the range of communication for the line of sight (LOS) mode? [use radius of the earth $= 6400$ km]
Answer: (C) $57.28$ km
$$d = \sqrt{2Rh_T} + \sqrt{2Rh_R} = \sqrt{2\times6.4\times10^6\times50} + \sqrt{2\times6.4\times10^6\times80}$$
$$d = 25.3\ \text{km} + 32.0\ \text{km} \approx 57.3\ \text{km}$$
Solution by Sreeraj P, M.Sc Physics