You are standing at a
distance d from a source that emits sound isotropically (equally in all directions).
You walk 50.0 m toward the source and observe that the intensity of the
waves has doubled. Calculate the distance d.
The distance d =
Using the fact that
we choose –d, we
will get a distance of 29.2 m, which is less than our walking distance of 50 m
toward the source.
relationship between the intensity of sound, at an observer a distance r
away from the source, and the power delivered by the source is
Let us apply this
relationship in for our situation.
The intensity a distance
d from the source is
Since the power is
constant, the intensity a distance (d-50) from the source is