Which term describes sound bending around obstacles?

• A. Reflection
• B. Diffraction
• C. Similarity
• D. Closure

Answer: (B)

Diffraction is the term that describes sound bending around obstacles. When a wave encounters an obstacle or passes through a small opening, it spreads out rather than traveling in a single straight line. For sound, this means the waves can wrap around a barrier and reach the other side, which is why you can hear someone speaking from behind a wall or around a corner. The effect is most noticeable when the obstacle’s size is comparable to the wavelength of the sound; long-wavelength, low-frequency sounds diffract more readily, while high-frequency, short-wavelength sounds show less bending. This phenomenon is distinct from reflection, where waves bounce off surfaces, and from perceptual terms like similarity or closure, which describe how we organize and complete sensory information rather than how waves propagate.