Q. In short wave communication, waves of which of the following frequencies will be reflected back by the ionospheric layer, having electron density $10^{11}\ per\ m^{3}$
A) 2 $MHz$
B) 10 $MHz$
C) 12 $MHz$
D) 18 $MHz$
Explanation
(a) By using $f_{c} \approx 9\left( N_{\max} \right)^{1/2} \Rightarrow f_{c} \approx 2\ MHz$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.