[填空题]
A 50-dB sound wave strikes an eardruvb2nhq cl ouud-m.-. 3 (*lewl1y5iuim whose areaapku gy 0iu-) ;kge0o9x(fj:z is $5 \times10^{ -5} m^2$ (a) How much energy is absorbed by the eardrum per second? $ \times10^{-12}$W (b) At this rate, how long would it take your eardrum to receive a total energy of 1.0 J? $ \times10^{ 3}$yr
