intensity / decibels of sound

[echoyjeff222]

Just curious if I will ever have to use the actual equation for intensity ... the 10*log[I/I0] one ... I seem to be getting by just knowing factor of 10 intensity --> 10 decibel places. Will I ever have to use the equation? And they seemed to give a "reference" intensity of 10E-12, but I don't see when I would ever use that, either.

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[t5Nitro]

Just curious if I will ever have to use the actual equation for intensity ... the 10*log[I/I0] one ... I seem to be getting by just knowing factor of 10 intensity --> 10 decibel places. Will I ever have to use the equation? And they seemed to give a "reference" intensity of 10E-12, but I don't see when I would ever use that, either.

It is unlikely you will have to actually use the equation to do a plug-and-chug question. Knowing what you know about the factors of 10 should be fairly sufficient. They may ask what happens if the intensity triples. In that case, dB = 10log(I/Io) turns into dB = 10log(3I/Io). You can break that into [10log(I/Io) + 10log(3)] so knowing a few common log numbers will be useful. The reference intensity you mentioned is the I_o term. But again, it is unlikely you will be doing a number crunch with that log(I/I_o) term.

Hope this helps.

 

[IslandStyle808]

It is unlikely you will have to actually use the equation to do a plug-and-chug question. Knowing what you know about the factors of 10 should be fairly sufficient. They may ask what happens if the intensity triples. In that case, dB = 10log(I/Io) turns into dB = 10log(3I/Io). You can break that into [10log(I/Io) + 10log(3)] so knowing a few common log numbers will be useful. The reference intensity you mentioned is the I_o term. But again, it is unlikely you will be doing a number crunch with that log(I/I_o) term.

Hope this helps.

True, but I would not put it past them though. On the official guide to the mcat, I was asked about intensity relative to distance (there was manipulation of that formula but to a simple degree like what you were showing).