The correct relation between plasma frequency `v` of a radio wave and electron density `N` of the ionosphere layer is

How is the critical frequency related to maximum electron density in the ionosphere?

The frequency range of radio-waves is ____

The relation between frequency n wavelength lambda and velocity of propagation v of wave is

Frequencies higher than 5 MHz are found not to be reflected by the ionosphere on a particular day at a place. The maximum electron density of the ionosphere is

The relation between frequency 'n' wavelength 'lambda' and velocity of propagation 'v' of wave is