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coconut62
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Homework Statement
A point source of sound emits energy equally in all directions at a constant rate and a person 8m from the source listens. After a while, the intensity of the source is halved. If the person wishes the sound to seem as loud as before, how far should he be now from the source?
A) 2m B) 2√2m C) 4m D) 4√2m
Homework Equations
Intensity (proportional sign) 1/distance[itex]^{2}[/itex]
Intensity (proportional sign) amplitude (not sure if needed)
The Attempt at a Solution
Answer: D
I = k/d[itex]^{2}[/itex] , where k is a constant.
I= k/8[itex]^{2}[/itex]
k = 64 I
(new I) x (new d[itex]^{2}[/itex]) = 64 I
(0.5 I) x new d[itex]^{2}[/itex] = 64I
new d[itex]^{2}[/itex]= 128
new d = 8√2 (no answer)
Sounds not very logical, but I don't know how am I wrong. Please explain to me.