IF ANYONE CAN NOT HEAR ULTRASONIC OR INFRASONIC SOUND HOW SCIENTISTS KNOW ABOUT THIS TERMS??? IS THIS A IMAGINATION OR SOMETHING ELSE????
Dear Student,
Sound is only audible to the average human ear if the frequencies lie between 20Hz and 20 kHz. Sound waves with frequencies less than 20Hz are called infrasonic or subsonic and those with frequencies above 20 kHz are called ultrasonic. Sources of infra sound in nature include volcanoes, avalanches, earthquakes and meteorites. Elephants, rhinoceroses and whales produce infrasonic sound waves. Bats and dolphins produce ultrasonic sound waves. Ultrasonic and infrasonic transducers are used to detect them. So they are not imaginary waves. We cannot hear them but we can experimentally detect them.
Regards.Sound is only audible to the average human ear if the frequencies lie between 20Hz and 20 kHz. Sound waves with frequencies less than 20Hz are called infrasonic or subsonic and those with frequencies above 20 kHz are called ultrasonic. Sources of infra sound in nature include volcanoes, avalanches, earthquakes and meteorites. Elephants, rhinoceroses and whales produce infrasonic sound waves. Bats and dolphins produce ultrasonic sound waves. Ultrasonic and infrasonic transducers are used to detect them. So they are not imaginary waves. We cannot hear them but we can experimentally detect them.