When discussing the behavior of waves, it is important to understand how amplitude, or the maximum displacement of a wave from its equilibrium position, changes as the distance from the source increases. In the case of sound and electromagnetic waves, which are both types of transverse waves, the amplitude decreases as the distance from the source is increased. This decrease in amplitude is due to the spreading of energy carried by the wave.
As waves propagate through a medium or through space, they spread out in two dimensions, forming a pattern of expanding circles or spheres. This spreading out of waves is referred to as wave divergence. As the wave travels away from its source, the energy it carries is distributed over a larger area, causing the amplitude to decrease.
The decrease in amplitude with increasing distance can be described by the inverse square law. This law states that the intensity, or power per unit area, of a wave is inversely proportional to the square of the distance from the source. Since the amplitude is directly related to the intensity of a wave, it follows that the amplitude also decreases as the square of the distance from the source.
To illustrate this concept, let’s consider the example of a sound wave. Imagine you are standing near a loudspeaker playing music. As you move away from the speaker, the sound becomes quieter. This decrease in volume is a result of the decreasing amplitude of the sound wave as it spreads out in all directions. The same principle applies to electromagnetic waves, such as light. If you observe a light source from a distance, you will notice that the brightness decreases as you move farther away.
In my personal experience, I have witnessed the effect of decreasing amplitude with increasing distance in various situations. For instance, when attending a concert, the music played by the band sounds much louder near the stage compared to being far away in the back of the venue. Similarly, when observing a firework display, the explosions appear more vibrant and intense when viewed up close, but as I move farther away, the brightness and impact of the fireworks diminish.
As waves propagate through a medium or through space, the amplitude decreases as the distance from the source increases. This decrease in amplitude is a result of the spreading out of energy carried by the wave. The inverse square law describes the relationship between intensity and distance, illustrating that the amplitude decreases as the square of the distance from the source. This phenomenon can be observed in various scenarios involving sound and electromagnetic waves, where the intensity or brightness of the wave diminishes as the observer moves farther away.