A small loudspeaker stands on a pole in an open field
PHYSICS · Multi-part · Fermi University Physics · Oscillations, Waves & Acoustics · Acoustics of fluids: generation, propagation and attenuation · Acoustics of fluids: generation, propagation and attenuation
Fluids and Continuum Physics, Ch Acoustics: sound propagation, radiation and attenuation
Problem
A small loudspeaker stands on a pole in an open field, far from any wall or hard ground, and radiates a steady tone equally in all directions. Its size is much smaller than the wavelength, so it may be treated as a small (monopole) source. Absorption of sound along the path is negligible over the distances used here. A meter 2.0 m from the speaker reads a sound level of 92 dB.
((a)) What level does a meter read at 8.0 m?
((b)) At what distance from the speaker does the level fall to 66 dB?