A sound absorber attenuates sound level by 20,, dB . intensity decrease by a factor of

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14.Waves and Sound

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A sound absorber attenuates the sound level by $20\,\, dB$. The intensity decrease by a factor of

A

$100$

B

$1000$

C

$10000$

D

$10$

Solution

$\Delta \mathrm{L}=\mathrm{L}_{1}-\mathrm{L}_{2}=10 \log \left(\frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}\right)$

$20 \mathrm{dB}=10 \log _{10}\left(\frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}\right)$

$10^{2}=\frac{\mathrm{I}_{1}}{\mathrm{I}_{2}} \Rightarrow \mathrm{I}_{2}=\frac{\mathrm{I}_{1}}{100}$

Standard 11

Physics

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