Two loudspeakers S1 and S2 each emit sounds of frequency 220 Hz uniformly in all directions. S1 has an acoustic output of 1.2×10−3 W and S2 has 1.8×10−3 W. S1 and S2 vibrate in phase. Consider a point P such that S1P=0.75 m and S2P=3 m. How are the phases arriving at P related? What is the intensity at P when both S1 and S2 are on? Speed of sound in air is 330 m/s.