For sky wave propagation of a ` 15 MHz` signal what should be the minimum electron density in ionosphere ?

Answer

`2.78 xx 10^(912) m^(-3)`

Explanation

Here , ` v_(c ) = 15 MHz = 15 xx 10^(6) Hz , N_(max) = ?`
As ` v_( c ) = 9 (N_(max))^(1//2)`
or `N_(max) = ((v_(c ))/( 9))^(2) = (v_( c)^(2))/( 81) = ((15 xx 10^(6))^(2))/(81)`
` = 2.78 xx 10^(12) m^(-3)`