Which term describes the low-pressure portion of a sound wave?

Which term describes the low-pressure portion of a sound wave?

• A. Compression
• B. Rarefaction
• C. Refraction
• D. Diffraction

Answer: (B)

Sound is a longitudinal wave, so its travel creates alternating regions of higher and lower pressure than the surrounding air. When particles are pushed closer together, that region is a compression and corresponds to higher pressure. When particles spread apart, that region is a rarefaction and corresponds to lower pressure. Thus, the low-pressure portion of the wave is a rarefaction. Refraction and diffraction describe how waves bend or spread as they encounter boundaries or different media, not the specific pressure state of a part of the wave.

Sound is a longitudinal wave, so its travel creates alternating regions of higher and lower pressure than the surrounding air. When particles are pushed closer together, that region is a compression and corresponds to higher pressure. When particles spread apart, that region is a rarefaction and corresponds to lower pressure. Thus, the low-pressure portion of the wave is a rarefaction. Refraction and diffraction describe how waves bend or spread as they encounter boundaries or different media, not the specific pressure state of a part of the wave.