Question

(i) Why do long-distance radio broadcasts use short-wave bands?
(ii) Why are optical and radio telescopes built on the ground, but X-ray astronomy is possible only from satellites orbiting the Earth?

Hint:

The Earth's atmosphere selectively allows certain frequencies (like optical and radio waves) while blocking others (like X-rays and gamma rays).

Answer 1

Long-distance radio broadcasts use short-wave bands because these bands undergo ionospheric reflection, allowing them to travel large distances beyond the line of sight.