声速测量实验中的三点思考  

Analysis of three questions in the experiment of measuring sound velocity

作　　者：江兴方[1] 

机构地区：[1]江苏石油化工学院信息科学系,江苏常州213016

出　　处：《大学物理》2002年第12期28-30,共3页College Physics

摘　　要：在声速测量实验中关于声波是否存在半波损失、声压波以什么样的形式衰减,许多大学物理实验教材上的叙述有所不同.本文从机械波的性质出发,指出声压波与声波位移波相位相差π2,解释了声波在传播过程中有半波损失,而实验结果似乎没有半波损失的现象.画出声压波的振幅衰减曲线,并提出利用双踪(或四踪)示波器采取相位比较法,可以直观地看出声压波形成的驻波相位变化的规律.The questions of halfwaveloss in the experiment of measuring of sound velocity: the curve of the amplitude, the sound pressure wave and the phase of the sound pressure wave are described differently in college physics experiments. Analysing the properties of mechanical wave, it is pointed out that the difference between the phase of the displacement wave and pressure wave is π2. This explains the seemingly selfcontradiction halfwaveloss in spreading of sound and no halfwaveloss in the result of the experiment. The curve of the amplitude of the sound pressure wave and the attenuation law of the curve are given. It shows a phase comparison method with doubletrace (or fourtrace) oscillograph is suggested.

关 键 词：声速测量实验 声压波 半波损失 衰减曲线 声波 双踪示波器 

分 类 号：O422.1[理学—声学]