Sound of 6.0 x 10^-3 W is produced by a loudspeaker which has a
surface area of 0.3m^2. The loudspeaker transfers 80% of its
acoustic energy to the front. Assume that the sound dissipates
equally in al directions towards the front. Calculate the intensity
right in front of the loudspeaker.
MUST WE ACTUALLY USE TAKE 80% OF THE POWER PRODUCED INSTEAD OF
TAKING 6.0 x 10^-3W????