Intensity of a Loudspeaker, What's wrong with calculation?

In summary, a certain loudspeaker system emits sound isotropically with a frequency of 1770 Hz and an intensity of 0.892 mW/m2 at a distance of 5.66 m. Using the equation for displacement amplitude, the answer for part b is 5.895 x 10-6 m. However, this answer may be incorrect and further calculations are needed. The question about pressure amplitude remains unanswered.
  • #1
Malavin
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0

Homework Statement


A certain loudspeaker system emits sound isotropically with a frequency of 1770 Hz and an intensity of 0.892 mW/m2 at a distance of 5.66 m. Assume that there are no reflections. (a) What is the intensity (in mW/m2) at 30.8 m? At 5.66 m, what are (b) the displacement amplitude and (c) the pressure amplitude of the sound? Take the speed of sound to be 343 m/s and the density of air to be 1.21 kg/m3.

I mostly need help with part b, I believe I can get part c with the answer from part b.

Homework Equations



I = 1/2(ρvω2sm2)

The Attempt at a Solution



So, for part b and from the relevant equation:

sm = (2I/ρvω2)1/2

ω = 2πf = 2*3.14159*1770 = 11121.24 Hz

So, using the above equation and plugging in I = 0.892 mW/m2, ρ = 1.21 kg/m2, and v = 343 m/s, I get the answer 5.895 x 10-6 m. However, this answer is apparently wrong, and I'm not sure why. Is there something wrong with my calculations?
 
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  • #2
intensity is the power/area covered. Such areas are usually spherical. so at a distance of 5.66meters,

.892E6W=
8.92E5W/m^2=power(dE/dt)/4pie(5.66)^2 if this really is a sphere and get power using algebra.

once you get power, intesity=power/4pie(30.8)^2 I don't get neither b or c. lol I didnt study pressure yet. I don't even know what amplitude affects.
 

Related to Intensity of a Loudspeaker, What's wrong with calculation?

1. What is the definition of intensity of a loudspeaker?

The intensity of a loudspeaker refers to the amount of sound energy that is transmitted per unit time over a unit area. In other words, it measures the loudness or strength of the sound produced by a loudspeaker.

2. How is the intensity of a loudspeaker calculated?

The intensity of a loudspeaker is calculated by dividing the power of the sound wave (measured in watts) by the area over which the sound is spread (measured in square meters). This gives the intensity in units of watts per square meter (W/m2).

3. Can the intensity of a loudspeaker be too high?

Yes, the intensity of a loudspeaker can be too high. If the intensity is too high, it can cause discomfort, pain, or even permanent damage to the ears. This is why it is important to follow safety guidelines and not expose yourself to loud sounds for extended periods of time.

4. What factors can affect the accuracy of intensity calculations for a loudspeaker?

There are several factors that can affect the accuracy of intensity calculations for a loudspeaker. These include the distance between the loudspeaker and the measuring device, the direction of the sound wave, and any obstructions or reflections that may affect the sound wave.

5. How can I improve the accuracy of my intensity calculations for a loudspeaker?

To improve the accuracy of intensity calculations for a loudspeaker, it is important to measure the sound at a consistent distance and angle from the loudspeaker, and to account for any obstructions or reflections. Using multiple measuring devices and averaging the results can also help to improve accuracy.

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