Waves and Sounds

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Intensity of Sound at a Concert

WAVES-L$KM1Y

Rita has a concert coming up this weekend but wasn't able to get her family seats sitting together. She has already purchased a few seats on the main floor 15 meters from the stage. The only other seats available are on the floor 3 meters behind the purchased seats or on the balcony 9 meters directly above the seats she has already purchased. If Rita wants to make sure all of her family enjoys about the same sound intensity, should she purchase the remaining floor seats or the balcony seats? The sound intensity of the performance in the already purchased seats is an average of $6.3\times 10^{ -3 }\cfrac { W }{ { m }^{ 2 } } $.

Assume there is no reflection of sound and the sound from the concert is a point source radiating equally in all directions.

A

The floor seats because the intensity of sound at the floor seats is closest to that of the originally purchased floor seats.

B

The balcony seats because sound travels faster through open air than through seated audience members.

C

The floor seats because the intensity of sound is the same for points along the same line.

D

The balcony seats because the intensity of sound in the balcony is closest to that of the originally purchased floor seats.