o waves, from the same source, have a path len form constructive or destructive interference?

At an outdoor music event, a dB meter records 130 dB when placed 2.25 m in front of aloudspeaker near the stage. A) What was the power output of the speaker, assuminguniform spherical spreading of the sound and neglecting any absorption, reflection andinterference of the sound that may occur? B) How far away would you need to be forthe sound level to be 80 dB?

Have seen some wrong answers by repeating the question which I don't want :(( Please don't answer like previous one You have been asked to predict the wave heights incident on the Fremantle railway bridge due to a wave train with offshore wave height of 1.15 m and period 14 s. The following information is given: (a) refraction analysis indicate that the spacing between the orthogonals is one half the deep water spacing. (b) water depth at the entrance to Fremantle harbour is 10m whilst at the Railway bridge it is 5 m. (c) width of river at the ocean entrance is 600 m and at the railway bridge is 100 m, respectively. [Neglect diffraction and frictional effects and approach the problem from energy considerations]

FM radio station KRTH in Los Angeles broadcasts on an assigned frequency of 101 MHz with a power of 50,000 W. (a) What is the wavelength of the radio waves produced by this station? (b) Estimate the average intensity of the wave at a distance of 36.1 km from the radio transmitting antenna. Assume for the purpose of this estimate that the antenna radiates equally in all directions, so that the intensity is constant over a hemisphere centered on the antenna. (c) Estimate the amplitude of the electric field at this distance.