- #1

hiuting

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## Homework Statement

The sound level in a noisy classroom is 101 dB. How much energy in J is transmitted to the outside through an open window of height 2 m and width 2.75 m, if the class is 40 minutes long?. What is the decibel rating 1 km from the classroom, assuming sound is distributed equally in all directions?

## Homework Equations

I = P / 4(pi)r

^{2}

[tex]\beta[/tex] = 10log(I/I

_{0})

## The Attempt at a Solution

the answers are [P = 0.069 W; E = 166 J; 46.4 dB]

I tried finding v, but I don't know what the dimensions of the window are for.