Two identical loudspeakers S1 and S2 are placed 0.80m apart along the x-axis and emit coherent sound waves of frequency 400Hz in phase. The speed of sound in air is 320ms−1. A point P lies on the line joining the speakers at a distance 2.20m from S1.
(i) Find the wavelength of the sound produced by the speakers.
(ii) Determine the path difference between the two waves reaching point P.
(iii) Calculate the corresponding phase difference at P.
(iv) State, with reason, whether constructive or destructive interference occurs at point P.