(II) You are trying to decide between two new stereoamplifiers. One is rated at 75 W per channel and the otheris rated at 120 W per channel. In terms of dB, how muchlouder will the more powerful amplifier be when both areproducing sound at their maximum levels?

(III) Expensive amplifier A is rated at 220 W, while the moremodest amplifier B is rated at 45 W. (a) Estimate the soundlevel in decibels you would expect at a point 3.5 m from aloudspeaker connected in turn to each amp. (b) Will theexpensive amp sound twice as loud as the cheaper one?

(a) Ear trumpets were never very common, but they did aid people with hearing losses by gathering sound over a large area and concentrating it on the smaller area of the eardrum. What decibel increase does an ear trumpet produce if its sound gathering area is 900 cm2 and the area of theeardrum is 0.500 cm2 , but the trumpet only has an efficiency of 5.00% in transmitting the sound to the eardrum?(b) Comment on the usefulness of the decibel increase found in part (a).