Question

The acoustical system shown in the figure below is driven by a speaker emitting sound of frequency 781 Hz. (Use v 343 m/s.) Sliding section Receiver Speaker (a) If constructive interference occurs at a particular instant, by what minimum amount should the path length in the upper U-shaped tube be increased so that destructive interference occurs instead? m (b) What minimum increase in the original length of the upper tube will again result in constructive interference? m

Answer 1

In Interference path difference beth two consicutine maxima & minima l ² So minimum path length increase in upper u-shape tube must be equy to , to change from Constructive to disbuchre af Disbructive to constructive (a) to change Constructive to distructive minimum increase in a 2 as u=fx path length (6) = 343 78182 -0. 219 m n o 27 Cha 0.22m to change constructive to Instructing minimum increase in - x path length = 343 28) = 0.439m 4 0.44m.