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<br />Theoretical Change in Sound Level <br /> <br />· Sound from a point source obeys the inverse square law. <br />II1'.~el~se S(III~lre L'~l'lr, SOIIII(1 <br /> <br />The sound intensity from a point s OUfC e of sound will obey the invers e s quare law if there <br />are no refle ctions or reverb eration. A plot of this intensity drop shows that it drop s off <br />rapidly. <br /> <br />~;ere ;ea <br />4rrr? <br /> <br />source power <br />p <br /> <br /> <br />intensity at <br />S ufface of sph e re <br />P = I <br />4rrr2 <br /> <br />The ene rgy twice as far from the <br />t: Ource it: spread ever ~QU r ti rnes <br />the a reEl, ....e nce one- fou nh the in tensiiY. <br /> <br />Source: Georgia State Univ. Web Site <br />