本题目来源于试卷: Physics Unit12: Sound，类别为 国际高中通用物理
[单选题]
At a distance of 15 m from a sou9ki+ge.cdh 2)+ r gjmjnd source the inten1.b lf3n 8c(uduu +cw)+29s+unvnti zz zrcp 5sity level is 60 dB. What is the intensity level (in dB) at a point 2.0 m from the source? Assume that the source radiu+3cuv u cbl z tn)1d+czr spn(.8n29+z uf5iwates equally in all directions.
A. $55.7 \; dB$
B. $57.5 \; dB$
C. $75.5 \; dB$
D. $77.5 \; dB$
参考答案: D
本题详细解析:
暂无
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