In the context of waves, the amplitude refers to the maximum displacement or height of the wave from its equilibrium position. The frequency, on the other hand, represents the number of complete wave cycles that occur in a given time interval.
When a wave propagates through a medium, such as air, water, or a solid, it experiences a phenomenon known as attenuation or damping. Attenuation causes the energy of the wave to gradually decrease as it travels through the medium. This energy loss leads to a decrease in the amplitude of the wave over distance.
Attenuation can occur due to various factors, including absorption, scattering, and dispersion. These factors depend on the properties of the medium and the type of wave being transmitted. For example, in sound waves traveling through air, attenuation occurs as the air molecules absorb and scatter the energy of the wave, causing its amplitude to diminish.
On the other hand, the frequency of a wave is determined by its source and remains constant as the wave propagates through a homogeneous medium. The frequency represents the number of wave cycles occurring per unit time, and it is not affected by the wave's distance traveled.
To summarize, the amplitude of a wave decreases over distance due to attenuation, which is the loss of energy as the wave propagates through a medium. The frequency, however, remains the same since it is determined by the source and is unaffected by distance.