Question

A $TV$ transmission tower has a height of $240\, m$. Signals broadcast from this tower will be received by line of sight communication at a distance of (Radius of earth $= 6.4 \times 10^6\, m$)

• A. $100\, km$
• B. $110\, km$
• C. $55 \,km$
• D. $120\, km$

Answer 1

Answer: (C)

Here, $h = 240 \,m$, $R = 6.4 \times 10^{6} \,m$
The maximum distance on earth from the transmitter upto which a signal can be received is
$d = \sqrt{2Rh} = \sqrt{2\times\left(6.4\times10^{6}\right)\times240}$
$= 55.4 \times 10^{3}\,m = 55.4\,km$