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同学们,八年级物理已经讲了,人耳能听到的声音频率在20赫兹到20000赫兹之间,低于20赫兹的叫次声波,高于20000赫兹的叫超声波。现在给大家谈谈次声波和超声波。
My classmates, Year 8 physics have said that the human ear can hear sound frequencies between 20 Hz and 20,000 Hz, sub-waves below 20 Hz and ultrasound waves above 20,000 Hz. Now talk to you about infrasound and ultrasound.