Physics question
2007-05-19 2:57 am
why we used to use ultrasound to detect the deep of the sea why not use other EM wave
回答 (2)
2007-05-19 3:51 am
✔ 最佳答案
雷達是用作探測空中的物體而聲納是用來探測水中的物體。 但雷達若用於水中，是不可以的。因為雷達是使用微波，微波的頻率和水的共振頻率相近，它是會被水吸收(如微波爐)，所以便很難穿過水，再利用物體的反射來探測水中的物體。
2007-05-19 3:55 am
The frequency of ultrasound is very high,
so by speed=frequency X wavelength
wavelength of ultrasound is very small
Hence,it shows very little diffraction
So it is easier to detect the reflected wave
when compared to other EM waves
so by speed=frequency X wavelength
wavelength of ultrasound is very small
Hence,it shows very little diffraction
So it is easier to detect the reflected wave
when compared to other EM waves
參考: myself
收錄日期: 2021-05-03 01:34:37
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070518000051KK03092