What is the intensity of the sound at A in W/m^2?

Question

At point A, 3.80m from a small source of sound that is emitting uniformly in all directions, the intensity level is 56.0 dB.
I JUST CAN'T SEEM TO GET THIS ONE RIGHT AND I DON'T KNOW WHAT I'M DOING WRONG. PLEASE HELP ME :) !!!!!!

Answer 1

From wikipedia:

For sound intensity, I0 is typically chosen to be 10^−12 W/m2, which is roughly the threshold of hearing. When this choice is made, the units are said to be "dB SIL". For sound power, P0 is typically chosen to be 10^−12 W, and the units are then "dB SWL".

The value of 56.0 db is derived from the formula

db = 10*log(I/I0)

For 56 db, I/I0 = 10^5.6 From the above reference, I0 = 10^-12 W/m^2; Therefore I = 10^5.6*10^-12 = 10^-6.4 W/m^2

Since the distance from the source was given in your problem, perhaps it meant "power level" rather than "intensity level". If that is the case, you would figure the power using the formula
db = 10*log(P/P0), just as above, except that P0 is 10^-12 watts. To get intensity at point A, divide by the spherical area at that point A = 4πr^2, where r = 3.8m