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LOTS OF NOISE III You are standing in the middle of a large room listening to a

ID: 1783587 • Letter: L

Question

LOTS OF NOISE III

You are standing in the middle of a large room listening to a cacaphony of sounds. Rank the intensity level of the sounds from each source (1=loudest, 2= next loudest, ...) Consider all objects to be right next to you. (Remember that if you have a tie, you skip some ranks.) If two values are within 0.1 dB from each other, consider them to be the same.
1 2 3 4  Four buzzers each producing a sound with intensity level of 71dB.
1 2 3 4  An object emitting a sound with an intensity of 80dB.
1 2 3 4  Two buzzers each producing a sound with intensity level of 76dB.
1 2 3 4  Ten buzzers each producing a sound with intensity level of 68dB.

Explanation / Answer

Item1 : Each buzzer of 71 Db

number of buzzers = 4

Total sound intensity = 10 Log[ 10^(71/10) + 10^(71/10) + 10^(71/10) + 10^ (71/10)]

= 10 [ log 4 + 7.1 log 10] = 77 db

Item2:

Intensity of sound object = 80db

Item3:

2 buzzers each 76 db

Total sound intensity = 10log[ 10^(76/10) + 10^(76/10)] = 10 [ log ( 2 X log 10^(7.6)]

= 79db

Item4:

Ten buzzers 68db each

Total intensity = 10 log[ 10X 10^(68/10)]

= 78 db

Item 2 is loudest 80db

item 3 is next loudesr at 79db

item 4 at 78db is the next loudest

item 3 at 77 db is the lowest intensity.