Question

If the radius of earth is R and height of a satellite above earth's surface is R then find the minimum co-latitude (in degree) which can directly receive a signal from satellite.

Answer 1

$\theta$-(0 latitude)

$\sin \theta =\frac{R}{R+R}=\frac{R}{2R}$

$\theta ={\sin }^{-1}\frac{1}{2}=30°$