Name the waves used for sound ranging. State one reason for their use. Why are the waves mentioned by you not audible to us?

Ultrasonic waves are used for sound ranging.

Ultrasonic waves can travel undeviated through a long distance and so they are used for sound ranging.

The range of audible sound waves is 20 Hz to 20,000 Hz, whereas ultrasonic waves have a frequency more than 20,000 Hz. Hence, ultrasonic waves are not audible to humans.