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InterviewSolution
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The loudest painless sound produces a pressure amplitude of 28 Nm^2. Calculate the intensity of this sound wave at S.T.P. Density of air at ST.P.=1.3 kg m^(-3) speed of sound at S.T.P.= 332 m/s. |
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Answer» Solution :`y=a sin (omegat -kx)` is the equation of PROGRESSIVE wave of 1/2 `rhoa^2omega^2v` is its intensity `P=(Edy)/(dx), v=sqrt(E/RHO)` `=v^2 rho (-ak) (cos omegat-kx)=v^2 rho ak sin (omegat-kx-pi//2)` `therefore P_(max)=v^2 rho ak` `therefore l=1/2rho(P_"max"^2)/(v^4 rho^2 k^2) v^2k^2 v "" {omega/k=v}` `=1/2 rho_"max"^2/(rhov) =1/2 xx28^2/(1.3xx332)=0.91 W-m^2` |
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