In short wave communication waves of which of the following frequeuncies will be reflected back by the ionospheric layer having electron density `10^(11)per m^(3)`?

Options

A. 2 MHz
B. 10 MHz
C. 12 MHz
D. 18 MHz

Explanation

Here, `N=10^(11)` per `m^(3)`, As `v=9sqrt(N)=9sqrt(10^(11))`
`=9xx3.16xx10^(5)=28.3xx10^(5)=2.83xx10^(6)Hz`
`-2.83 MHz`
So waves of frequency 2 MHz will be reflected back by the ionosphere layer.