A harmonic sound wave of wavelength 0.85m is travelling through air along a straight line.
(a) Two points A and B on the same line of propagation are separated by 1.275m. Calculate the phase difference between the vibrations of particles at A and B.
(b) Determine the minimum separation along the direction of propagation between two points that always vibrate in opposite phase (antiphase).
(c) The speed of sound in air is 340m s−1. For a fixed particle of the medium, find the smallest time interval after an instant t=0 at which its displacement again becomes opposite to what it was at t=0.