Question

The area of the region covered by the TV broadcast by a TV tower of 100 m height is (Radius of the earth = $6.4 \times 10^6 \, m$ )

• A. $12.8 \pi \times 10^8 \, km^2$
• B. $1.28 \pi \times 10^3 \, km^2$
• C. $0.644 \pi \times 10^3 \, km^2$
• D. $1.28 \pi \times 10^3 \, km^2$

Answer 1

Answer: (B)

$1.28 \pi \times 10^3 \, km^2$

Answer 2

Area of broadcast is
A = $\pi d^2 = \pi \, ( 2hR )$
Given, $h = 100 mR = 6.4 \times 10^6 \, m$
$\Rightarrow A = \pi ( 2 \times 100 \times 6.4 \times 10^6 )$
A = $1.28 \pi \times 10^3 \, km^2$