[填空题]
Expensive amplifier A is rated at 250 W, whil 3b hxdj5vi8*be the a x)ya,d9vvki 03v8rj more modest amplifier B is rated at 40 W. (a) Estimate the sound level in decibels you would expect at a point 3.5 m from a loudspeaker3j8k,9r vviy)x v0ada connected in turn to each amp.$I_{250}$ = dB $I_{40}$ = dB (b) Will the expensive amp sound twice as loud as the cheaper one?
