Question

People with good hearing can perceive sounds as low in level as –8.00 dB at a frequency of 3000 Hz. What is the intensity of this sound in watts per meter squared?

Answer 1

You can use the relationship:
`I(dB)=10log(I/I_0)`
Where `I_0=10^(-12) W/m^2` represents the intensity just audible (correspnding to `0 dB`).
So:
`-0.08=10log(I/10^(-12))`; power `10` both sides and rearrange:
`I=9.8xx10^-13 W/m^2`