Calculating Energy Absorbed by Eardrum from Intensity & Area

[jmb07]

A sound wave with intensity of 80.1 dB is incident on an eardrum of Area = 0.7x10^-4. How much energy is absorbed by the eardrum in 4 minutes?


I know this much... Power = (Intensity)(Area)..so...P=(80.1)(0.7x10^-4)

and Energy = (power)(time) so...E = (80.1)(0.7x10^-4)(240 sec) = 1.35


However, this is not the correct answer. Am i not doing the right conversions or what?? What looks wring here? (the correct answer is 1.72)

I know it probably has something to do with converting dB to something...im just not sure how..

 

[LowlyPion]

Isn't a decibel a log of the ratio of the sound to a reference level?

So ... 80.1 dB = 10log₁₀(P1/Po)

Po is what? 10^-12W/m² ?