1.

A certain source of sound waves radiates uniformly in all directions. At a distance of 20 m from the source the intensity level is 51 db. What is the total acoustic power output of the source, in watts? (Note: The reference intensity 10 is 1.0 x 10-12 W/m2.) Give your numerical answer in Watts in decimal form with 2 significant figures please.Determine the sound intensity level 30.0 m from a sound source that emits 20.0 W of acoustical power spread equally in all directions. The threshold of hearing is 1.0 X 10'12 W/m2. O 92.5 dB 0 81.5 dB 0 1.77 X 10-3 dB 0 1.77 X 10-3 W O -27.5 dB A 2.4-m long gas column that is open at one end and closed at the other end has a fundamental resonant frequency 69.0 Hz. What is the speed of sound in this gas? A pipe that is 0.46 m long and open at both ends vibrates in the second overtone with a frequency of 1150 Hz. In this situation, the distance from the center of the pipe to the nearest antinode is closest to O 7.7 cm. 0 3.8 cm. 0 12 cm. 0 15 cm. Q zero. You are driving along a highway at 35,0 in/s when you hear the siren of a police car approaching you from behind and you perceive the frequency as 1310 Hz. You are relieved that he is in pursuit of a different Speeder when he continues past you. but now you perceive the frequency as 1240 Hz. What is the frequency of the siren in the police car? The speed of sound in air is 343 mas. o 1270 Hz 0 1300 Hz 0 1320 Hz 0 1360 Hz O 1370 Hz