Describe the term virtual height with the help of diagram showing ionized layer and the path of wave.

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Virtual height: -The incident wave returns back to the earth due to refraction. In this process it bends down gradually and not sharply, but the incident and reflected rays follow exactly the same paths as those if the signal have been reflected from a surface located at greater height. It is the height above the earth’s surface from which a refracted wave appears to have been reflected. It is also defined as the maximum height that the hypothetical reflected wave would have reached. 

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