Question

49)Sound of frequency below …………… is called infrasonic sound.

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Answer 1

Answer:

20Hz

Explanation:

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Answer 2

Answer:

20 hz

Explanation:

(“Infra” and “ultra” are from the Latin, meaning “below” and “beyond,” respectively.) The nominal range of human hearing extends from about 20 Hz to 20 000 Hz, so the inaudible sound waves with frequencies below 20 Hz were dubbed infrasound, while those above the upper limit of 20 000 Hz were named ultrasound.