storm warning siren emits sound uniformly in all directions. Along a line that is drawn radially outward from the sound source (the siren) determine the positions of two points, 0.47 m apart, such that the intensity level at one point is 4.22 dB greater than the intensity level at the other. point closer to siren ?
Properties of sound
A sound wave is a mechanical wave (or mechanical vibration) that transit through media such as gas (air), liquid (water), and solid (wood).
Quality Of Sound
A sound or a sound wave is defined as the energy produced due to the vibrations of particles in a medium. When any medium produces a disturbance or vibrations, it causes a movement in the air particles which produces sound waves. Molecules in the air vibrate about a certain average position and create compressions and rarefactions. This is called pitch which is defined as the frequency of sound. The frequency is defined as the number of oscillations in pressure per second.
Categories of Sound Wave
People perceive sound in different ways, like a medico student takes sound as vibration produced by objects reaching the human eardrum. A physicist perceives sound as vibration produced by an object, which produces disturbances in nearby air molecules that travel further. Both of them describe it as vibration generated by an object, the difference is one talks about how it is received and other deals with how it travels and propagates across various mediums.
A storm warning siren emits sound uniformly in all directions. Along a line that is drawn radially outward from the sound source (the siren) determine the positions of two points, 0.47 m apart, such that the intensity level at one point is 4.22 dB greater than the intensity level at the other.
| point closer to siren ? |
apply Intensity level B = 10 dB log(I/Io)
here given B2-B1 = 4.22
so
Intensity level B2-B1 = 10 dB log ( I2/I1)\
Log(I2/I1) = 4.22/10 = 0.422
I2/I1 = 10^0.422 = 2.642
also I = intensity = pOWER/area
so I2/I1 = r1^2/r2^2 = 2.642
r1/r2 = 1.625
r1 = 1.625 r2 (equation 1)
but given r1-r2 = 0.47 (equation 2)
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