Need Help-Sound (1 Viewer)

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

I need help for this problem. I tried applying the formula B=10log(I/Io) but I don't get right answer. Someone help me or give me suggestion/hint about what to do? The problem is as follows: At a rock concert, a dB meter registered 130gB when placed 2.8m in front of a loudspeaker on the stage. a) What was the power output of a speaker, assuming uniform spherical spreading of the sound and neglecting absorption of air? b) How far away would the sound level be a somewhat reasonable 90 dB?
 
250
1
what answer do you get?
I would have thought that you would use the decibel equation you have to solve for I. Then once you have the intensity you can solve for [tex]P_a_v_e[/tex] given that you know the distance away from the source and that it is spherical spreading with no attenuation through air.

I=P/A

Where A is the surface area of a sphere: [tex]4(\pi)r^2[/tex]

Does this give the wrong answer?
 

The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top