(1) Audible or Sound Waves : The longitudinal mechanical waves which lie in the frwquency range 20 Hz to 20000 Hz are called audible or sound waves.
These waves are sesitive to human ear. These are generated by the vibrating bodies such as tuning fork, vocal cords etc.
(2) Infrasonic Waves : The longitudinal mechanical waves having frequencies less than 20 Hz are called Infrasonic.
These waves are produced by source of bigger size such as earth quakes, volcanic eruptions, ocean waves and by elephants and whales.
(3) Ultrasonic Waves : The longitudinal mechanical waves having frequencies greater than 20000 Hz are called ultrasonic waves.
Human ear can not detect these waves. But certain creatures like dog, cat, bat, mosquito can detect these waves. But not only detect but also produce ultrasonic.
