Jayhawk1
Apr17-05, 11:45 PM
Here is the trouble problem...
11) A tornado warning siren on top of a tall pole radiates sound waves uniformly in all directions. At a distance of 15 m the sound intensity of the siren is 0.39 . Neglect any effects from reflection of the sound waves from the ground. a) At what distance from the siren is the intensity 0.19 ? b) What is the total acoustical power output of the siren? c) At what distance is the sound intensity reduced by 15 dB from its level at 15 m?
a) 21.5 m
b) 1100 Watts
Ok... so I figured out parts a and c, but I have no clue for part c- and the same seems to go for most of my class. I think the change might be very small, but I don't know how to get it. Any help would be appreciated. Thanks!
11) A tornado warning siren on top of a tall pole radiates sound waves uniformly in all directions. At a distance of 15 m the sound intensity of the siren is 0.39 . Neglect any effects from reflection of the sound waves from the ground. a) At what distance from the siren is the intensity 0.19 ? b) What is the total acoustical power output of the siren? c) At what distance is the sound intensity reduced by 15 dB from its level at 15 m?
a) 21.5 m
b) 1100 Watts
Ok... so I figured out parts a and c, but I have no clue for part c- and the same seems to go for most of my class. I think the change might be very small, but I don't know how to get it. Any help would be appreciated. Thanks!