For long distance radio broadeast, we use short wave only. Why?

why is short wave communication over long distance not possible by surface wave propagation ?

What is the advantage of using a transformer for long distance transmission of electrical energy?

Why should there be a long distance transport system in plants?

A LASER is a source- of very intense, monochromatic, and unidirectional beam of light. These properties of a laser light can be exploited to measure long distances. The distance of the Moon from the Earth has been already determined very precisely using a laser as a source 'of light. A laser light beamed at the Moon takes 2.56 s to return after reflection at the Moon’s surface. How much is the radius of the lunar orbit around the Earth?

Debate the following issue in class. the estimated coal reserves are said to be enough to last us for another two hundred years. Do you think we need to worry about coal getting depleted in this case ? Why or why not ?