Physics · Ch 11 — Waves
Reflection of Sound Waves
Reflection of Sound Waves
When a sound wave travelling through one medium meets a boundary with a second medium, one of two things can happen: reflection, in which the medium at the boundary is dense/rigid enough that the sound bounces back essentially completely into the original medium, or refraction, in which the sound instead partly transmits into the second medium, typically losing some energy to absorption there. This section focuses specifically on reflection: it first states the basic laws governing how sound reflects off plane and curved surfaces (obeying exactly the same laws as the reflection of light), and then surveys the everyday and technological applica …
What this figure shows. Four separate small panels show sound wavefronts (drawn as curved arcs) striking and reflecting off four different surface shapes in turn: a smooth plane surface, a convex surface, a concave surface, and a corner (two surfaces meeting at a right angle). In each panel incoming arcs are shown bending back after striking the surface, with the plane-surface panel showing the reflected arcs mirroring the incoming ones symmetrically, the convex panel showing the reflected arcs spreading further apart than before, the concave panel showing the reflected arcs bending inward toward a common focus, and the corner panel showing sound reflected back roughly toward its original direction after two successive bounces. The figure previews, all on one page, the different reflection behaviours -- described individually in …