A concert loudspeaker suspended high above the ground emits 35 W of sound power. A small microphone with a 1.0 cm² area is 50 m from the speaker.a. What is the sound intensity at the position of the microphone?

Which of the following statements is explained best using the Chargaff's rule?

Assuming that the maximum displacement of the air molecules in a sound wave is about the same as that of the speaker cone that produces the sound (Fig. 16–46), estimate by how much a loudspeaker cone moves for a fairly loud (105 dB) sound of

(b) 35 Hz. <IMAGE>

(I) What are the lowest and highest frequencies that an ear can detect when the sound level is 40 dB? (See Fig. 16–6.)

(II) Expensive amplifier A is rated at 280 W, while the more modest amplifier B is rated at 45 W.

(b) What output wattage amp would sound about twice as loud as the 45-W amp?