Inverse Square Law HELP PLEASE

[RichardGib]

Homework Statement

If I measure a sound intensity of 1.0 at distance R from its source, what intensity would I measure at distance 3R in a free, unbounded space? What is the difference in decibels?

&

If I measure a sound pressure of 1.0 at distance R from its source, what pressure would I measure at distance 2R in a free, unbounded space? What is the difference in decibels?

Homework Equations

N/A

The Attempt at a Solution

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I am stuck on this. i thought the answer to the first question could be a difference of -18db? Really stuck here...

Thankyou!

 

[Fightfish]

The inverse square law simply means that the value of the physical observable involved is inversely proportional to the square of the distance from the source. That is to say, for instance if the distance is doubled, then the value falls to a quarter (half squared).

 

[BvU]

Hello Richard, welcome to PF :)

Please check the PF guidelines (especially #4); the way you post now actually prevents us from helping you further.

And you can read up on the subject a little here

 

[RichardGib]

Hello Richard, welcome to PF :)

Please check the PF guidelines (especially #4); the way you post now actually prevents us from helping you further.

And you can read up on the subject a little here

Thankyou :)