Question

Which of the following use space wave mode of propagation?
A) Television broadcast
B) Microwave
C) Satellite communication
D) All of the above

Answer 1

The radio waves having high frequencies are called space waves. These waves can go through the environment, this is called the space wave method of propagation. At such high frequencies other techniques for wave engendering can't work, along these lines space wave propagation is utilised. As transmission, Microwave and satellite correspondence all utilise the high recurrence space waves. Consequently, all these utilize the space wave method of spread.

Complete step by step answer:
In our environment, there are lots of waves travelling across the world. Different types of waves travel in different modes of propagation. Here we discuss about some of the important waves-

1. Ground waves: Ground waves are electromagnetic waves allude to engendering of radio waves corresponding to and neighbouring the outside of the earth. It is called ground waves because all these waves are the more unequivocally diffracted around impediments because of their long frequencies permitting them to follow the earth space.

2. Ionosphere waves: The ionosphere is a piece of upper atmosphere locates of the words air principally because of getting bright radiation from the Sun albeit different sources for example Grandiose beams.

3. Sky waves: The energy transmitted by a receiving wire that is Sky wave would squandered energy taking everything into account in the event that it proceeded on its way and did not Re-visitation of earth yet under specific conditions it is reflected from the ionosphere.

4. Space waves: The radio waves having high frequencies are essentially called space waves. Examples of radio waves, microwaves, television broadcast etc. .These waves can spread through air from transmitter reception apparatus to beneficiary radio wire. These waves can travel straightforwardly or can go in the wake of reflecting from earth’s surface to the lower atmosphere surface of Earth. Thus, it is likewise called tropospheric propagation.
   Hence, all of the waves are called space waves and use wave mode of propagation.

Therefore, option D is correct.

Note:
All waves that have high frequencies propagate similar to the space wave. The frequencies of these waves lie between $30mHz$ to $300mHz$. These waves make Ultra high frequency bands.