Q. An antenna is of height 500 m. What will be its range (Radius of earth is 6400 km)?
A) 800 km
B) 100 km
C) 50 km
D) 80 km
Explanation
(d) Suppose height of antenna is $h.$ Due to curvature of earth the TV signals will be received on earth in a circle of radius $d.$ Reception range is given by
$d = \sqrt{2hR}$
Here, $h = 500\ m,\ R = 6400\ km$
$\therefore d = \sqrt{2 \times 500 \times 6400 \times 10^{3}}$
$= 80000\ m = 80\ km$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.