(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

a)A sound wave with an intensity level of 80.1 dB is incident on an eardrum of area 0.600 10-4 m2. Calculate the energy is absorbed by the eardrum in 4.00 minutes in microJ

b)The sound level 25.0 m from a loudspeaker is 69.0 dB. Calculate the rate at which sound energy is produced by the loudspeaker, assuming it to be an isotropic source.

2. Relevant equations

3. The attempt at a solution

We know tha the refernece intensity (I0) = 10-12W/m2

We know that sound intensity level is

β = 10dB log (I/Io)

Then 80.1dB = 10dB log (I/Io)

8.01 = log (I/Io)

Now finding I then substitue in the equation

I =P/A

= E/AΔt

Then the area covered by the sound is

A = 0.600 10-4 m2.

Then energy is absorbed by the eardrum in 4.00 minutes ( i.e 4*60s = 240s) in μJ.

E = IAΔt

I got 1.44x10^{-14}(which ended up being wrong))

b)

We know tha the refernece intensity (I0) = 10-12W/m2

We know that sound intensity level is

β = 10dB log (I/Io)

Then 69dB = 10dB log (I/Io)

6.9 = log (I/Io)

Now finding I then substitue in the equation

I =P/A

Then the area covered by the sound is

A = 4π(25.0m)2

= 7850m2

Now the total power of the source is

P = IA in W Or J/s

I got 7.85x10^{-9}please help. what am I doing wrong?

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# Homework Help: Sound Energy & Intensity

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