Question

The increase in the height of the tower of height $200\,m$ to get its coverage range tripled is

• A. 800 m
• B. 1600 m
• C. 900 m
• D. 700 m

Answer 1

Answer: (B)

1600 m

Answer 2

Coverage range, $d = \sqrt{2Rh}$
where R is the radius of the earth and h is the height of a tower .
$d \propto\sqrt{h}$
$\therefore \:\:\:\:\:\frac{d}{3d} = \sqrt{\frac{h}{h}}$ or $\frac{1}{9} = \frac{h}{h'}$

or $h' = 9h = 9 \times 200 \, m = 1800 \, m$
Increase in the height of the tower
$= h' -h = 1800 \, m - 200\, m = 1600 \, m$