199k views
5 votes
Two loudspeakers emit sound waves along the x-axis. A listener in front of both speakers hears a maximum sound intensity when speaker 2 is at the origin and speaker 1 is at x = 0.540 m . If speaker 1 is slowly moved forward, the sound intensity decreases and then increases, reaching another maximum when speaker 1 is at x = 0.870 m .

What is the frequency of the sound? Assume velocity of sound is 340m/s.
What is the phase difference between the speakers?

User Sener
by
5.6k points

2 Answers

5 votes

Final answer:

The frequency of the sound waves is 1030.3 Hz, calculated using the wavelength that corresponds to the distance where maximum sound intensity is heard again. The phase difference between the speakers is π radians.

Step-by-step explanation:

To determine the frequency of the sound waves emitted by the speakers, we can use the phenomenon of constructive interference and the concept of sound wave interference. Constructive interference occurs when two waves combine to make a wave with a larger amplitude, which happens at the positions of maximum sound intensity that the listener hears.

Given that the sound intensity reaches a maximum again when speaker 1 is moved from 0.540 m to 0.870 m, we can deduce that this distance, 0.330 m, corresponds to one wavelength (λ) since this is the distance needed for speaker 1 to be 'in phase' again with speaker 2.

Using the wave equation v = fλ, where v is the velocity of sound and f is the frequency, we can solve for the frequency:

f = v / λ

f = 340 m/s / 0.330 m

f = 1030.3 Hz

For the phase difference between the speakers, when speaker 1 is at 0.540 m, it is λ / 2 out of phase with speaker 2 at the origin because it is at a position of constructive interference, and moving it half a wavelength results in another constructive interference. This translates to a phase difference of π radians (180°).

User WNRosenberg
by
5.2k points
2 votes

Answer:

frequency of the sound = f = 1,030.3 Hz

phase difference = Φ = 229.09°

Step-by-step explanation:

Step 1: Given data:

Xini = 0.540m

Xfin = 0.870m

v = 340m/s

Step 2: frequency of the sound (f)

f = v / λ

λ = Xfin - Xini = 0.870 - 0.540 = 0.33

f = 340 / 0.33

f = 1,030.3 Hz

Step 3: phase difference

phase difference = Φ

Φ = (2π/λ)*(Xini - λ) = (2π/0.33)* (0.540-0.33) = 19.04*0.21 = 3.9984

Φ = 3.9984 rad * (360°/2π rad)

Φ = 229.09°

Hope this helps!

User Gitau Harrison
by
5.6k points