- #1

jangchen

- 12

- 3

- Homework Statement:
- A loudspeaker, mounted on a tall pole, is engineered to emit 75% of its sound energy into the forward hemisphere, 25% toward the back. You measure an 85 dB sound intensity level when standing 3.5 m in front of and 2.5 m below the speaker. What is the speaker’s power output?

- Relevant Equations:
- dB = 10 log(I / Io) , I = P / 4pi×r^2

I is proportionate to E.

r = 4.3xxm

So I put 0.75I

The answer is 49mW..

But I got 97.xxmW

What is wrong?

r = 4.3xxm

So I put 0.75I

The answer is 49mW..

But I got 97.xxmW

What is wrong?