You are trying to overhear a juicy conversation, but from your distance of 20.0 m, it sounds like only an average whisper of 20.0 dB. So you decide to move closer to give the conversation a sound level of 70.0 dB instead. How close should you come?

Given that,

Distance = 20.0 m

Average whisper = 20.0 dB

Sound level = 70.0 dB

We know that,

The minimum intensity is

We need to calculate the sound intensity in the distance of 20 m

Using formula of sound intensity

Put the value into the formula

If the conversation a sound level of 70.0 dB instead

We need to calculate the sound intensity

Using formula of sound intensity

Put the value into the formula

We know that,

The intensity is inversely proportional with the square of the distance.

We need to calculate the distance

Using formula of intensity

Put the value into the formula

Hence, The distance from the conversation should be 0.063 m.