Q. If sky wave with frequency of 50 MHz is incident on $D$ region at an angle of $30{^\circ}$, then angle of refraction is
A) $15{^\circ}$
B) $30{^\circ}$
C) $60{^\circ}$
D) $45{^\circ}$
Explanation
(b) For D-region, $N = 10^{9}\ m^{- 3}$
$\mu = \sqrt{1 - \frac{81.45\ N}{v^{2}}} = \sqrt{1 - \frac{81.45 \times 10^{9}}{\left( 50 \times 10^{6} \right)^{2}}} = 1\ $
$\mu = \frac{\sin i}{\sin r} = 1$
Or $\sin r = \sin i\ or\ \ r = i = 30{^\circ}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.