1) A loudspeaker at a concert genertes 2.00x10^-2 W/m^2 at a distance of 25.0m and all of its acoustic energy is radiated uniformly into a forward facing hemisherical surface. The frequency is .00kHz. There is no acoustic power "lost" as it transmits through the air.
a) What is the sound level in dB 25.0m from the stage?
b) What is the total power radiated by the loudspeaker?
c) At what distance from the loudspeaker would the sound level drop to 90.0dB?
2) The G-string on a violin is 30.0cm long. When played without touhing it the string vibrtes at 196 Hz. The next highest notes in the C-major scale are A (220Hz), B(247Hz), and C(262 Hz). How far from the closest end of the string must a finger be pressed down onto the neck of the instrument such that these three high notes are produced in succession?
3) An explosion occurs, releasing 1.00kJ of energy, 1.00% of which goes into a spherical sound wave traveing away equally in all directions. A sound level meter located 8.92m from the explosion records a level of 110.dB during a time interval equal to the duration of the explosion. How long did the explosion last?