1. The problem statement, all variables and given/known data A sound source, detector and a movable wall are arranged as shown in the figure. In this arrangement detector is detecting the maximum intensity. If the speed of sound is 330 m/s in air and frequency of source is 600 Hz, then find the distance by which the wall should be moved away from the source, so that detector detects minimum intensity. 2. Relevant equations 3. The attempt at a solution I don't quite understand the situation. Do the waves reflected by the wall ever reach the detector? I don't see how the reflected waves would reach the detector. (Can I assume that the waves get reflected the same way as a light ray would? ) Any help is appreciated. Thanks!