In short wave communication, waves of which of the following frequencies will be reflected back by the ionospheric layer having electron density 10¹¹ per m ^3 ?

Step-by-step solution

We know that the artificial frequency of a sky wave for reflection from an ionospheric layer of the atmosphere is given by, v_c=9 N^ 1 / 2 where n is the number density of electrons / m ^3 . It is given that N=10¹¹ / m ^3 v_c=9 (10¹¹ )^ 1 / 2 =2.8 10^6 ~Hz =2.8 MHz . Hence the wave of frequency 2 MHz will be reflected back.