A.聲壓與媒質(zhì)體積速度之比 B.聲壓與媒質(zhì)質(zhì)點(diǎn)速度之比 C.聲壓與流阻之比 D.聲壓與風(fēng)阻之比
A.3倍 B.2倍 C.1.5倍 D.1.3倍
A.1~5ms B.5~10ms C.10~20ms D.5~30ms