下列叙述中不正确的是()。 ["在波的传播方向上,相位差为2π的两质元间的距离称波长","机械波实质上就是在波的传播方向上,介质各质元的集体受迫振动","波由一种介质进入另一种介质后,频率、波长、波速均发生变化","介质中,距波源越远的点,相位越落后"]
频率为500Hz的机械波,波速为360m/s,则同一波线上位相差为的两点相距为()。 ["0.24m","0.48m","0.36m","0.12m"]
下列哪项不是党参的主治病证() ["A.中气不足","B.肺气亏虚","C.津伤口渴","D.血虚萎黄","E.阴虚发热"]
下列哪项不是龟甲的功能() ["A.滋阴","B.潜阳","C.止血","D.养心","E.健脾"]
在同一介质中两列相干的平面简谐波的强度之比是I1/I20=4,则两列波的振幅之比是()。 ["A1/A2=4","A1/A2=2","A1/A2=16","A1/A2=1/4"]
证券发行审核制度包括两种,即:()和()。