Two identical sine waves are superimposed on one another creating a beat pattern. How far out of phase are the two waves? The speed of sound is 340 m/sec.

a. 180

b. 10

c. 90

d. 360

when two sine waves are superimposed on one another, a beat pattern is observed. this beat pattern consists of high intensity and low intensity in sequence alternately. we get the high intensity pattern when the two waves meet in phase and we get low intensity when the two waves are out of phase. the intensity is lowest when the two wave are completely out of phase or 180 degree phase difference between the waves.

hence correct choice is a. 180