Need help w/ problem: Sound intensity and energy

[ryoon4690]

Homework Statement

A fan at a rock concert is 30 from the edge of the stage. The sound intensity level at the edge of the stage is 110 dB. The fan's eardrums have a diameter of 8.4 . How much energy is transferred to each eardrum in one second? (Hint: It may help to asume that the speaker is on the stage located 1.0 m from the edge.) Answer should be expressed in Joules.

Homework Equations

I=P/4πr^2, β=(10dB)log(I/Iinitial)

The Attempt at a Solution

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Thanks for your help!

 

[ideasrule]

Why did you leave the distance units out when telling us the distance from the stage and the diameter of the eardrums?

Anyhow, at 1 m from the speaker, sound intensity is 110 dB. What's the intensity 31 m away? (Hint: inverse square law.) Express that in watts per unit area, then multiply that by the eardrum's area, and you'll get the answer.