for a linear source in three dimensions, the wavefront are cylindrical. and intensity, I is inversely proportional to r ( distance from the source ) is the fact given correct?? here's the question. cylindrical wavefronts are emitted by a linear source of length 4.0 m, at a rate of 50 microwatt. what is the intensity of this wave at a distance of 60m from the source? i just want to check out whether the answers in the book is correct or not.. thank you.