Underwater illusion. One clue used by your brain to determine the direction of a source of sound is the time delay ?t between the arrival of the sound at the ear closer to the source and the arrival at the farther ear. Assume that the source is distant so that a wavefront from it is approximately planar when it reaches you, and let D = 0.227 m represent the separation between your ears. (a) If the source is located at angle ? = 31.0o in front of you (Fig. 17-30) and the air temperature is 20oC, what
is ?t (in ms)?