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

Electromagnetic waves of frequencies higher than 9sqrt(2) MHz are found to be not reflected by the ionosphere on a particular day at a place. The maximum electron density in the ionosphere is :