In general, if a sound has intensity of β db at 1 m from the source, at what distance from the source would the decibel level decrease to 0 db? since the limit of hearing is 1 db this would mean you could no longer hear it. express the answer in terms of β. possibly relevant information: the sound of normal breathing is not very loud, with an intensity of about 11 db at a distance of 1 m away from the face of the breather. again: express the answer in terms of β!

The required distance is given by

Explanation: The sound intensity in dB is given by the formula

where is the hearing threshold in absolute units and is the absolute intensity of the sound which depends on the distance. In general, for two distances and we have that

Now let us take and let be the required distance. We have

Exponentiating these equations we obtain

Dividing them

Using the previously stated identity

Now if we use the given example where we have

close lines strong magnet less close weaker

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