If sky wave with a frequency of 60 MHz is incident on D- region at an angle of `30^@`, then find the angle of refractive.

Explanation

For D-region, `N = 10^(9) m^(-3)`. Here `v = 60 xx 10^6 Hz`
Refractive index of the atmospheric layer is
`mu = [ 1- (81.45N)/v^2]^(1//2) = sqrt( 1- (81.45 xx 10^9)/(60 xx 10^6)^2) ~~1`
Now, `mu = (sin i)/(sin r) = 1 or sin i = sin r or r = i = 30^@` .