DecibelAns

# DecibelAns - ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ 1 p p from dB...

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z What is the intensity in dB IL of a sound with the following absolute powers? Key to answering these questions is to use the equation 10 log 12 10 X 1. 10 2 w/m 2 140 dB IL 2. 10 -8 w/m 2 40 dB IL 3. 10 1 w/m 2 130 dB IL 4. 10 -3 w/m 2 90 dB IL z What is the intensity in dB SPL of a sound with the following absolute pressures? Key to answering these questions is to use the equation 20 log 10 2 x X 1. 2000 μPa 40 dB SPL ( This absolute pressure can be written as 2 x 10 3 μPa ) 2. 2*10 6 μPa 100 dB SPL 3. 2*10 7 μPa 120 dB SPL 4. 2*10 8 μPa 140 dB SPL z Derive the equation dB SPL = 20 log
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Unformatted text preview: ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ 1 p p from dB IL = 10 log ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ 1 I I . Hint: Use the relation p 2 ∞ I . Start with the equation for dB IL, and substitute I by p 2 . So the first step would be dB SPL = 10 log ( ) ( ) ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ 2 2 1 p p . This is the same as 10 log 2 1 ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ p p , which is the same as 10 x 2 log ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ 1 p p , which is 20 log ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ 1 p p...
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