At a rock concert, a db meter registered 130 db when placed 2.5 m in front of a loudspeaker on stage. (a) what was the power output of the speaker, assuming uniform spherical spreading of the sound and neglecting absorption in the air? (b) how far away would the sound level be 85 db?

785.398 W

444.5698 m

Explanation:

I = Intensity of sound

r = Distance

The intensity of sound is given by

Power

The power output of the speaker is 785.398 W

If

The distance would be 444.5698 m

d) the number of neutrons plus the number of protons

the higher the current the higher the mag field around it the higher the influence on the compass