Give reasons for the following:
(i) Long distance radio broadcasts use short-wave bands.
(ii) The small ozone layer on top of the stratosphere is crucial for human survival.
(iii) Satellites are used for long distance TV transmission.

Explanation

(i) Because they can be reflected by the ionosphere of the Earth.s atmosphere and can be sent to longer distances.
(ii) The ozone layer absorbs the ultraviolet radiations coming from the Sun and prevents them from reaching the Earth.s surface.
(iii) As television signals are having high frequency, therefore, they cannot be reflected by ionosphere. To reflect these high frequency signals, satellites are required.