Physics

posted by .

Hi I am absolutely stumped on this question.

A loudspeaker is placed between two observers who are 110 m apart, along the line connecting them. If one observer records a sound level of 60.1 dB and the other records a sound level of 74.9 dB, how far is the speaker from each observer?

What I did for this is

I found the the Intensities of both the sound levels.
Then using the formula r1= SQRT(I2/I1)*R2

I would solve for r1 and then do r1+r2=113 to find r2.

I also don't know what value to assign for I2 and I1, i tried both ways but its wrong.

Please Help!

Thanks In Advance

  • Physics -

    The sound level difference is 14.8 dB. That means that the sound intensity ratio is 10^0.148 = 30.2

    That means one speaker is sqrt 30.2 = 5.50 times farther way from the source than the other. If x is the shorter distance

    x = 5.50 x = 6.50 x = 110 m.
    x = 16.9 m The other distace is 93.1 m

  • Physics -

    Hey sorry about the 3 posts, It was an accident.
    Just a quick question, why do you need to find the sound level difference?

  • Physics -

    One more thing,
    how did you find 10^0.148 be 30.2? isn't it 1.406. I do see you used a ratio, but what was divided?

  • Physics -

    I meant 10^1.48 = 30.2. Sorry about the typo. The 30.2 is correct. 1.48 is 1/10 of the dB difference in received sopund power levels.

    If it is a mystery where the 10^(0.1*dB difference)comes from, that is the definition of decibals in terms of intensity ratio

    Log10(I2/I1) = 1/10 (dB2 - dB1)

    10^[0.1(dB2-dB1)] = I2/I1

  • Physics -

    how do you get 6.50
    and the final answers to be 16.9m & 93.1m?

  • Physics -

    I2/I1 = (r2)^2/(r1)^2
    square root of (I2/I1) = r2/r1
    This will be the difference between the two.
    Therefore (distance between the two people/ square root of (I2/I1)) = smallest distance from loud speaker.
    And distance between the two people minus the smallest distance is the largest distance.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    Hi I am absolutely stumped on this question. A loudspeaker is placed between two observers who are 110 m apart, along the line connecting them. If one observer records a sound level of 60.1 dB and the other records a sound level of …
  2. Physics

    Hi I am absolutely stumped on this question. A loudspeaker is placed between two observers who are 110 m apart, along the line connecting them. If one observer records a sound level of 60.1 dB and the other records a sound level of …
  3. Physics

    Hi I am absolutely stumped on this question. A loudspeaker is placed between two observers who are 110 m apart, along the line connecting them. If one observer records a sound level of 60.1 dB and the other records a sound level of …
  4. physics

    A loudspeaker is placed between two observers who are 114 m apart, along the line connecting them. If one observer records a sound level of 61.6 dB and the other records a sound level of 81.3 dB, how far is the speaker from each observer?
  5. physics

    Posted by Anonymous on Tuesday, December 2, 2008 at 12:43am. A loudspeaker is placed between two observers who are 114 m apart, along the line connecting them. If one observer records a sound level of 61.6 dB and the other records …
  6. physics

    A loudspeaker is placed between two observers who are 111 m apart, along the line connecting them. If one observer records a sound level of 51.9 dB and the other records a sound level of 82.5 dB, how far is the speaker from each observer?
  7. physics

    A college student is at a concert and really wants to hear the music, so she sits between two in-phase loudspeakers, which point toward each other and are 60.8 m apart. The speakers emit sound at a frequency of 428.75 Hz. At the midpoint …
  8. physics

    A college student is at a concert and really wants to hear the music, so she sits between two in-phase loudspeakers, which point toward each other and are 60.8 m apart. The speakers emit sound at a frequency of 428.75 Hz. At the midpoint …
  9. Physics HELP!!

    A loudspeaker is placed between two observers who are 113m apart, along the line connecting them. If one observer records a sound level of 51.8dB and the other records a sound level of 75.8dB, how far is the speaker from each observer?
  10. math

    Each of two observers 475 feet apart measures the angle of elevation to the top of a tree that sits on the straight line between them. These angles are 55° and 59°, for observers A and B, respectively. How tall is the tree?

More Similar Questions