Physics Unit12: Sound (id: eab8ff114)

本题目来源于试卷: Physics Unit12: Sound，类别为 通用国际物理

[单选题]
Sound vibrations with frequencies greater /6 2la+mn aho(rqw- jvf(inb2than 20,000 Hz arqjq.wp0o97s(p4s(ly78ew t hqd0k qce called

A. infrasonics.
B. ultrasonics.
C. supersonics.
D. none of the above


参考答案:  B


本题详细解析: 暂无

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