Physics with Application; Acoustics; Trumpet

[MAtkinson]

From Acoustics, Resonance, Energy, Power, Intensity and The Doppler Effect

Homework Statement

An old-fashioned hearing trumpet has the shape of a flared funnel, with a diameter of 8 cm at its wide end and a diameter of 0.7 cm at its narrow end. Suppose that all of the sound energy that reaches the wide end is funneled into the narrow end. By what factor does this hearing trumpet increase the intensity of sound (measured in W/m2)? By how many decibels does it increase the intensity level of sound?

Homework Equations

Intensity = Power / Area

Intensity = Energy / (Time)*(Area)

Intensity Level = 10*Log(Intensity/10^(-12)) (db)

The Attempt at a Solution

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[Delphi51]

Welcome to PF!
We have a policy of ignoring questions where there is no attempt made on the problem. But I can make an exception since it is your first post, and offer a suggestion to get you started.

Start by finding the areas, at the input end and at the output to ear end. Put them into your formulas.

 

[MAtkinson]

... Thanks for the insightful reply. I understand it's not the most difficult question, nonetheless I am getting stuck.

10^((deltaIntensityLevel)/10-12)=Power/DeltaCircleArea

 

[Delphi51]

I don't understand that at all.
Were you able to find the two areas?
Maybe use intensity = power/area twice, once for each end.