Question

Two sound waves, from two different sources with the same frequency of 420 Hz travel in the same direction at 336 m/s. The sources are in phase. What is the phase difference of the waves at a point that is 4.40 m from one source and 4.00 m from the other?

Answer 1

Answer:

Pi(3.14) radians or 180º degrees

Explanation:

First of all, we need to obtain the wavelength of a wave traveling to the speed of sound and 420 Hz of frequency.

The formula is:

$l=wavevelocity/frequency$

where l = wavelength in meters

With current values:

l = 336 [m/s]/420[1/s] = 0.8 meters

Since a complete cycle (360º or 2pi radians) needs 0.8 meters to complete, 0.4 meters or 40 cm is just half of it, making a 180º degree phase or 3.14 radians.