1.The mass of a string is , and it is stretched so that the tension in it is 180 N. A transverse wave traveling on this string has a frequency of 260 Hz and a wavelength of 0.60 m. What is the length of the string?

2.A rocket engine emits of sound energy every second. The sound is emitted uniformly in all directions. What is the sound intensity level, measured relative to the threshold of hearing, at a distance of 85 m away from the engine?
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