Question

Long-distance communication between two points on the earth is achieved by
A) space wave communication
B) skywave communication
C)satellite wave communication
D)line of sight transmission

Answer 1

Hint: For long-distance communication, radio waves which can be easily reflected 2 other places must be used. One such wave is known as skywave. This wave is not limited by the curvature of the earth, it is easy to trance for information from one place to another place across the world easily.

Complete step-by-step solution
In radio communication, skywave refers to the radio waves that are reflected towards earth due to the presence of the ionosphere. The ionosphere is an electrically charged layer in the upper atmosphere. Skywave propagation is often wont to communicate beyond the horizontal, at intercontinental distances. It is mostly utilized in the shortwave frequency bands.
Therefore the correct option is option b.
Additional information:
Skywave transmissions can be used for long-distance communications by waves directed at a low angle as well as relatively local communications which are nearly vertically directed waves. The ionosphere is a region about 82,000 kilometers in altitude. In this region aries ionized by solar photon sand cosmic rays. When high-frequency signals enter the ionosphere at a low angle they are bent back towards the earth. With a peak ionization is strong enough for the chosen frequency it will exit the bottom layer hey. At surface then reflects the descending wave back up again towards in a sphere hey sometimes even signals a few watts can be received many thousands of miles away. This is the key point that enables shortwave broadcasts to travel all over the world.

Note: For near communication, the sky waves are directed vertically or almost vertically. This is because it gets reflected directly back to the ground and when it hits the ground it spreads out over a wide region if the receiver is present in that region spread by the waves the information can be transferred easily similar is the case of longer communication, the waves are projected at a low angle.