Why is sound heard fainter as air is pumped out of a bell jar containing a ringing bell?
ABecause the air is needed to carry the sound; with less air, less sound reaches the listener
BBecause the bell stops vibrating
CBecause the bell becomes cooler
DBecause vacuum amplifies all sounds equally
Answer & Solution
Correct answer: A. Because the air is needed to carry the sound; with less air, less sound reaches the listener
Sound is a vibration of particles in the medium. As air is removed, fewer air particles are available to transmit the vibration, so the sound becomes fainter. In a perfect vacuum, the sound would not reach the listener at all.
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