Question

i have many doubts today i asked about 10 questions
once more,ultrasonic waves
9th studebts please help ​

Answer 1

Answer:

You should say

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Answer 2

Answer:

I'm from 9 th class

Explanation:

Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" sound in its physical properties, except that humans cannot hear it. This limit varies from person to person and is approximately 20 kilohertz in healthy young adults.

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