Question

define ultra and infrasonic sounds.

Answer 1

the sound waves within the frequency range of 20Hz to 20000Hz are known as infrasonic wave or sound .
the sound waves of frequency higher than 20000Hz are known as ultrasonic wave or sound

Answer 2

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➡ Ultrasonic sound: The sounds of frequency more than 20,000 Hz are called ultrasonic sounds.

➡ Infrasonic sounds: The sounds of frequency less than 20 Hz are called infrasonic sounds.