Physics: Difference between revisions
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:* As the plane wave progresses, the wave does not expand. When the wave reaches a distance that’s double the original, the small area of the sound wave at the closer distance hasn’t spread at all, and as a result the intensity of the original piece of sound wave is the same. | :* As the plane wave progresses, the wave does not expand. When the wave reaches a distance that’s double the original, the small area of the sound wave at the closer distance hasn’t spread at all, and as a result the intensity of the original piece of sound wave is the same. | ||
[[Image:Untitled2.jpg|frame|center|A spherical-wave source, including virtually all existing loudspeakers, retains only one quarter of its intensity with each doubling of distance from the source. This is perceived as a rapid falloff of loudness with increasing distance. A cylindrical-wave retains half of its intensity with each doubling of distance from the source. This is perceived as a modest falloff of loudness with increasing distance. A plane-wave source loses no sound intensity with each doubling of distance from the source; in other words, the loudness is unchanged with increasing distance.]] | |||