Q 17.10: Receiver A detects a sound level of 75 dB at a distance of 25 m from a speaker, which emits sound equally in all directions. Receiver B detects a sound level of 55 dB from the same speaker. How far is receiver B from the speaker

250 m

Explanation:

We expect the distance to be more because the sound level has decreased.

Sound level (in decibels) is related to distance by

where is the sound level at a distance of and

is the sound level at a distance of .

Using the values in the question,

As a note, when distance increases by 10, the sound level drops by 20 dB, which is what we have in the question.

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