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Questions:
520. Decibels from I in watts/m²
530. I in watts/m² from decibels
540. dB level of combined sounds
545. dB level of combined sounds
 

 
520. How many decibels is a sound having intensity, I = 5x10^-8 watts/m²?

a) -73 dB
b) 4.7 dB
c) 47 dB
d) 62 dB

Fundamentals of Sound reference: Sec. 11-H.
 
 
 
 
 

530. What is the intensity in Watts/m² of an 89 decibel sound?

a) 7.9 x 10^-12 W/m²
b) 7.9 x 10^-4 W/m²
c) 8.9 x 10^-12 W/m²
d) 8.9 x 10¹² W/m²

Fundamentals of Sound reference: Sec. 11-H.
 
 
 
 
 

540. Five sound sources each at an intensity of 10^-2 W/m² are combined. What is the dB level of the combined sounds.

a) -1.3
b) -13
c) 10.7
d) 107
e) none of these

Fundamentals of Sound reference: Sec. 11-K.
 
 
 
 

545. A 30 dB and a 40 dB sound are combined. Which of the following is closest to the dB level of the combined sounds?
a) 34 dB
b) 70 dB
c) 40 dB
d) 42 dB
e) 44 dB

Fundamentals of Sound reference: Sec. 11-K.
 
 
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