Electromagnetic waves of frequency ……. are reflected from ionosphere.

Critical frequency that gets reflected back from ionosphere is

The e.m. waves of radio frequency cannot be reflected by ionosphere. (True/False)

The e.m. waves of radio frequency cannot be reflected by ionosphere. (True/False)

Electromagnetic waves with frequency greater than the critical frequency of ionosphere cannot be used for communication using sky wave propagation, because:

Electromagnetic waves with frequency greater than the critical frequency of ionosphere cannot be used for communication using sky wave propagation, because:

An eletromagnetic wave of frequency 28 MHz passes through the lower atmosphere of earth and gets incident on the ionosphere.Shall the ionosphere reflects these waves?