Physics
posted by Kyle on .
A fan at a rock concert is 45.0 m from the stage, and at this point the sound intensity level is 108 dB. Sound is detected when a sound wave causes the tympanic membrane (the eardrum) to vibrate . Typically, the diameter of this membrane is about 8.40 m in humans
I solved for the intensity using Beta = (10 dB) log I/I_0
I got I to be 3.11*10^5 W/m^2 45m away.
Then I found the energy to be 17.22*10^11J
The answer wants it in micro joules but I'm not even sure if I've done the problem correctly.

I don't understand the diamter being 8meters. It makes no sense.
Secondly, What is the exact question? 
oh sorry the diameter is 8.4mm
and the question is asking for the
How much energy is transferred to her eardrums each second ? 
108=10 log(I/Io)
10.8=log( )
I= 10^10.8 * Io=10^10.8*1E12=.063watts/m^2 check that.
Energy= areadrum*I= PI* .004^2*I above.
= .063watts/m^2*PI*16E6=3.2 × 106 watts. 
108=10 log(I/Io)
10.8=log( )
I= 10^10.8 * Io=10^10.8*1E12=.063watts/m^2 check that.
power= areadrum*I= PI* .004^2*I above.
= .063watts/m^2*PI*16E6=3.2 × 106 joules/sec
energy in one second= 3.2E6joules 
The range away from the stage doesn't matter?

the range doesnt matter because the relative intesity is already given in db