A sound wave of 40.0 cm wavelength enters
the tube shown in the figure at the source end. What must be the smallest
radius r of the curved path such that a maximum intensity will be heard at
the detector end?
The smallest value of r is
Sound travels through two
through the curved tube L1 and
through the straight tube L2 . The path length difference between the two sound
Since we want maximum sound at the detector, the relationship between the path length
difference and the wavelength is
But since we want a non-zero value of r, we take the smallest
non-zero of DL.