Answer the following questions:(a) Long-distance radio broadcasts use short-wave bands. Why?(b) It is necessary to use satellites for long-distance TV transmission. Why?(c) Optical and radio telescopes are built on the ground, but X-ray astronomy is possible only from satellites orbiting the earth. Why?(d) The small ozone layer on top of the stratosphere is crucial for human survival. Why?(e) If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now?(f) Some scientists have predicted that a global nuclear war on the earth would be followed by a severe ‘nuclear winter’ with a devastating effect on life on earth. What might be the basis of this prediction?

(a) Ionosphere reflects waves in the shortwave bands.
(b) Television signals have high frequency and high energy. Therefore, it is not properly reflected by the ionosphere. Satellites are used to reflect the TV signals.
(c) Atmosphere absorbs X-rays, while visible and radio waves can penetrate it.
(d) Ozone layer absorbs the ultraviolet radiation from the sunlight and prevents it from reaching the surface of the earth and causing damage to life.
(e) If the earth did not have an atmosphere, there would be no greenhouse effect. As a result, the temperature of the earth would decrease.
(f) The smoke clouds produced by global nuclear war would perhaps cover substantial parts of the sky, preventing solar light from reaching many parts of the globe. This would cause a ‘winter’.