96.8k views
0 votes
g power output of 87 W. At what distance will the decibel reading be 120 dB, which is noise level of a loud indoor rock concert

User Pinwheeler
by
7.4k points

1 Answer

4 votes

Given that,

Output power = 87 W

Decibel reading = 120 dB

We need to calculate the intensity of sound

Using formula of intensity of sound


dB=10\log((I)/(I_(0)))

Put the value into the formula


120=10\log((I)/(1*10^(-12)))


12=log((I)/(1*10^(-12)))


10^(12)=(I)/(1*10^(-12))


I=10^(12)*1*10^(-12)


I=1\ W/m^2

We need to calculate the distance

Using relation of power out[ut and intensity


I=(P)/(4\pi r^2)

Put the value into the formula


1=(87)/(4\pi r^2)


r=\sqrt{(87)/(4\pi)}


r=2.63\ m

Hence, The distance is 2.63 m

User Ostergaard
by
6.9k points