The radio waves are electromagnetic wave, so it travels with velocity of light i.e 
.
We can use the relation between frequency, wavelength and speed as
Here c is speed of light, 
is wavelength and f is frequency and its value is given 99.90 FM, it is actually in megahertz (i.e 99.90 MHz).
Therefore,
.
Thus, the broadcast wavelength of the given radio station is 3.003 m.
Humans hear frequencies from 20 Hz<span> (low) up to </span>20,000 Hz (high)
Answer: the refraction of light by the atmosphere
Explanation: Refraction is the phenomenon in which there is a change in direction of light passing from one medium to another or from a gradual change in the medium.
Here in case of sunset, the sun rays passes through the varying density of atmosphere because of varying concentrations of dust particles.
Reflection is the phenomenon in which the light bounces back after falling on a surface.
Absorption is the phenomenon in which matter captures the electromagnetic radiations and thus the energy of photons is converted to internal energy of the system.
What is a travelling wave and a standing wave? What are the differences between both of them?
Answer: First of all we have to understand that a traveling wave is an organized disturbance traveling with a well defined wave speed. On the other hand standing waves are the combination of period waves with their reflected waves creating double sided waves. The differences between them is that standing waves have nodes and antinodes while a traveling wave does not.
I hope it helps, Regards.
