posted by .

An audio speaker at a concert emits sound uniformly in all directions at a rate
of 100 W.
(i) Calculate the sound intensity experienced by a listener at a distance
of 8 m from the speaker.
The listener moves back from the speaker to protect her hearing.
(ii) At what distance
from the speaker is the sound intensity level reduced by 3 dB?

  • physics -

    I = P/A = P/4πr² = 100/4π(8)² = 0.12 W•m⁻²
    If the sound intensity level is halved to a value of I = 0.06 W•m⁻²,
    the sound intensity level will decrease by 3 dB.
    I = P/4πr² = 100/4π(x) ² =
    =0.06 W•m⁻²
    x = 11.5 m from the speaker.

  • physics -


Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    This time I have two questions: #1.A recording engineer works in a soundproofed room that is 49.7 dB quieter than the outside. If the sound intensity in the room is 2.66 x 10-10 W/m2, what is the intensity outside?
  2. physics

    The Doppler effect occurs when a) a source of sound moves toward a listener b) a listener moves toward a source of sound c) a listener and a source of sound move away from each other d) a listener and a source of sound move toward …
  3. math

    A loud speaker at a rock concert generates 102 W/m2 at 20m with a frequency of 1 kHz. Assume that the speaker spreads its intensity uniformly in all direction. (a) What is the sound level ( = ?
  4. physics

    1. A sound is made by a speaker, which then radiates in all directions. The sound wave is described by A(r) sin(2r - 600t) where the distances are in meters, and the time in seconds. The A(r) just indicates that the amplitude has some …
  5. physics

    A student in the front row of a concert is at a distance of 2 m from the speaker. They hear the sound at 140dB. What is the sound intensity if the student walks 20 m away. What is the sound intensity at 2 m if there are 100 speakers …
  6. physics

    NEED HELP WITH ONLY PART C Two 135.1.0-W speakers, A and B, are separated by a distance D = 3.6 m. The speakers emit in-phase sound waves at a frequency f = 11800.0 Hz. Point P1 is located at x1= 4.50 m and y1 = 0 m; point P2 is located …
  7. Physics

    A speaker at an open-air concert emits 600 of sound power, radiated equally in all directions. a)What is the intensity of the sound 7.00 from of the speaker?
  8. Physics(Please respond)

    A source emits sound uniformly in all directions. There are no reflections of the sound. At a distance of 12 m from the source, the intensity of the sound is 1.7 × 10-3 W/m2. What is the total sound power P emitted by the source?
  9. Maths

    Mathew is attending a very loud concert by the discarded. To avoid permanent ear damage he decides to move farther from the stage. Sound intensity is given by the formula I=k/d*d where k is the constant and d is the distance in metres …
  10. Physics

    There is a band who uses 10000 W to radiate sound energy in all directions. What was the intensity of sound 10 meters from this speaker?

More Similar Questions