本题目来源于试卷: SoundSoundSoundSound，类别为 IB物理学
[问答题]
A noisy truck approachxw fnkc)h4 l-be3iu.2es you from behind a building. Initially y scow,k o(/mn+h7s q0*qrwz: wou hear it but cannot see it. When it emerges and you do see it, its sound is suddenly “brighter” — you hear more of the high-frequency noise. Explain. [Hint: Seeoq/0s mcw ,qk (wsw o:hrzn*+7 Section 11–15 on diffraction.]
参考答案: When
you first hear the truck, you cannot see it.
There is no straight line path from the truck to you. The sound waves that you are hearing are
therefore arriving at your location due to diffraction. Long wavelengths are diffracted more than
short wavelengths, and so you are initially only hearing sound with long
wavelengths, which are low-frequency sounds.
After you can see the truck, you are able to receive all frequencies
being emitted by the truck, not just the lower frequencies. Thus the sound “brightens” due to your
hearing more high frequency components.
本题详细解析:
暂无
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