Question

The sound level produced by one singer is 70.8 dB. What would be the sound level produced by a chorus of 37 such singers (all singing at the same intensity at approximately the same distance as the original singer)

Answer 1

Answer:

86.48 dB . Ans

Explanation:

Sound level by one singer = 70.8 dB

= 7.08 B

If I be its intensity in terms of watt/m²

log ( I / 10⁻¹² ) = 7.08 ( given )

I / 10⁻¹²  = 10⁷°⁰⁸

I = 10⁻¹² x 10⁷°⁰⁸

= 10⁻⁴°⁹²

= .000012022 W / m²

intensity by 37 singers

= 37 x .000012022 W /m²

= .0004448378

= 4448.378 x 10⁻⁷

intensity level

= log I / 10⁻¹² B

= log 4448.378 x 10⁻⁷ / 10⁻¹²

= log 444837800 B

log 4448378 + 2 B

= 6.6482 +2 B

8.6482 B

intensity level = 8.6482 B

= 86.48 dB . Ans

Answer 2

Answer:

86.48 dB

Explanation:

86.48 dB

Explanation:

sound level intensity, β = 70.8 dB  

Io = 10^-12 W/m²

Let the intensity if I at the level of 70.8 dB  

Use the formula  

 

 

7.08 = log I + 12

log I = - 4.92  

I = 1.2 x 10^-5 W/m²

There are 37 singers, so the total intensity is I'.  

I' = 37 x I  

I' = 37 x 1.2 x 10^-5 = 4.45 x 10^-4 W/m²

Let the sound intensity is β' in decibels.  

Use the formula  

 

 

β' = 86.48 dB